Difference between revisions of "Bovine Forelimb - Anatomy & Physiology"

From WikiVet English
Jump to navigation Jump to search
(38 intermediate revisions by 6 users not shown)
Line 1: Line 1:
−
{{OpenPagesTop}}
+
{{no pics}}
 +
 
 +
{{toplink
 +
|backcolour =CDE472
 +
|linkpage =Musculoskeletal System - Anatomy & Physiology
 +
|linktext =Musculoskeletal System
 +
|maplink = Musculoskeletal System (Content Map) - Anatomy & Physiology
 +
|pagetype =Anatomy
 +
|sublink1=Forelimb - Anatomy & Physiology
 +
|subtext1=FORELIMB
 +
}}
 +
<br>
 
==Structures of the Proximal Forelimb and Shoulder==
 
==Structures of the Proximal Forelimb and Shoulder==
  
 
===Scapula===
 
===Scapula===
−
 
+
*The ox possesses a small '''tuber scapular'''
−
The ox possesses a small '''tuber scapular''', it has an '''acromion''' present and has extensive scapular cartilage.
+
*It has '''acromion''' present
 +
*It has extensive scapular cartilage
  
 
===Humerus===
 
===Humerus===
 +
*The humerus is essentially the same conformation as that of the dog.
  
−
The humerus is essentially the same conformation as that of the dog.
 
  
 
===Radius and Ulna===
 
===Radius and Ulna===
 +
*These are complete bones in the ox but are entirely fused
 +
*There is a proximal and distal interosseous space which are the only two places where the shafts are seperated
 +
*The ulna's proximal end is caudal to the radius and it's distal end forms the lateral styloid process, distal to the radius and articulating with the ulnar carpal bone.
  
−
These are complete bones in the ox but are entirely fused. There is a proximal and distal '''interosseous space''' which are the only two places where the shafts are separated. The ulna's proximal end is caudal to the radius and its distal end forms the '''lateral styloid process''', distal to the radius and articulating with the ulnar carpal bone.
 
  
 
==Joints of the Proximal Forelimb==
 
==Joints of the Proximal Forelimb==
 
===Shoulder Joint===
 
===Shoulder Joint===
  
−
The joint capsule attaches a very short distance from the periphery of the articular surfaces. The '''intertubercular (bicipital) bursa''' lies between the humeral tubercles cushioning the bicipital tendon. The bursa and tendon are held in place by the '''transverse humeral retinaculum''', running between the greater and lesser tubercles of the humerus.
+
*The joint capsule attaches a very short distance from the periphery of the articular surfaces.
 +
*The '''intertubercular (bicipital) bursa''' lies between the humeral tubercles cushioning the bicipital tendon.
 +
*The bursa and tendon are held in place by the '''transverse humeral retinaculum''' running between the greater and lesser tubercles of the humerus.
  
 
===Elbow Joint===
 
===Elbow Joint===
  
−
The joint capsule attaches to the articular surface of the condyle, the periphery of the '''olecranon fossa''' and the articular  cartilage of the '''trochlear notch of the ulna'''. It fuses with the collateral ligaments. Paired collateral ligaments attach the epicondyles to the tuberosities of the radius and ulna.
+
*The joint capsule attaches to the articular surface of the condyle, the periphery of the olecranon fossa and the articular  cartilage of the trochlear notch of the ulna. It fuses with the collateral ligaments.
 +
*Paired collateral ligaments attach the epicondyles to the tuberosities of the radius and ulna.
 +
 
  
 
==Structures of the Distal Forelimb==
 
==Structures of the Distal Forelimb==
Line 27: Line 45:
 
===Carpal bones===
 
===Carpal bones===
  
−
The carpal bones comprise two rows:
+
Carpal bones comprise two rows:
 +
*Proximally, (mediolaterally), radial, intermediate, ulnar and accessory bones
 +
*Distally, 1st is missing, 2 and 3 are fused
  
−
'''Proximally''' (mediolaterally), radial, intermediate, ulnar and accessory bones.
+
===Metacarpal bones===
  
−
'''Distally''', 1st is missing, 2 and 3 are fused and there is also a 4th carpal bone.
+
These are covered in detail in the [[Bovine Phalanges - Anatomy & Physiology|bovine phalanges]] section.
−
 
 
−
===Metacarpal bones===
 
  
−
These are covered in detail in the [[Bovine Lower Limb - Anatomy & Physiology|bovine lower limb]] section.
 
  
 
==Joints of the Distal Forelimb==
 
==Joints of the Distal Forelimb==
Line 41: Line 58:
  
 
The carpal joint is a compound joint composed of:
 
The carpal joint is a compound joint composed of:
 +
*The '''antebrachiocarpal joint''' between the radius/ulna and the proximal carpal bones
 +
*The '''middle carpal joint''' between the two rows of carpal bones
 +
*The '''carpometacarpal joint''' between the distal carpal bones and the proximal metacarpals
  
−
1. The '''antebrachiocarpal joint''' between the radius/ulna and the proximal carpal bones.
+
The joint is a synovial joint, comprised of a common outer fibrous capsule and three inner synovial pouches, one for each joint.  
−
 
+
*'''Collateral ligaments''' extend from the radius to the metacarpal bones on the medial and lateral aspect of the carpus.
−
2. The '''middle carpal joint''' between the two rows of carpal bones.
+
*The carpal canal houses both the deep digital flexor tendon and the deep branch of the superficial digital flexor.
  
−
3. The '''carpometacarpal joint''' between the distal carpal bones and the proximal metacarpals.
 
−
 
−
The joint is a synovial joint, consisting of a common outer fibrous capsule and three inner synovial pouches, one for each joint. '''Collateral ligaments''' extend from the radius to the metacarpal bones on the medial and lateral aspect of the carpus. The carpal canal houses both the deep digital flexor tendon, and the deep branch of the superficial digital flexor.
 
  
 
==Muscles of the Forelimb==
 
==Muscles of the Forelimb==
 
===Extrinsic Musculature===
 
===Extrinsic Musculature===
  
−
These muscle are responsible for joining the forelimb to the trunk, forming a synsarcosis rather than a conventional joint. Collectively, they act to transfer the weight of the body to the forelimbs as well as stabilize the scapula.
+
These muscle are responsible for joining the forelimb to the trunk, forming a synsarcosis rather than a conventional joint. Collectively, they act to transfer the weight of the body to the forelimbs as well as stabilize the scapula.
  
−
'''''Trapezius''''':
+
'''''Trapezius''''': Accessory n.
−
:Innervated by: Accessory n.
+
*Origin: mid-dorsal raphe and supraspinous ligament
−
:Origin: mid-dorsal raphe and supraspinous ligament.
+
*Insertion: spine of the scapula
−
:Insertion: spine of the scapula.
+
*Body: two parts, cervical and thoracic separated by aponeurosis
−
:Body: two parts, cervical and thoracic separated by aponeurosis.
+
*Action: raises scapula against the trunk and swings cranially to advance the limb
−
:Action: raises scapula against the trunk and swings cranially to advance the limb.
 
  
−
'''''Brachiocephalic m.''''':
+
'''''Brachiocephalic m.''''': Accessory n.
−
:Innervated by: Accessory n.
+
*Two parts separated by the clavicle where it exists
−
:The two parts are separated by the clavicle, where it exists.
+
*Origin: occipital bone, nuchal ligament, mastoid process
−
:Origin: occipital bone, nuchal ligament and the mastoid process.
+
*Insertion: deltoid tuberosity and fascia of limb
−
:Insertion: deltoid tuberosity and fascia of the limb.
+
*Actions:  
−
:Actions: advances the limb and extends the shoulder joint when limb is in motion. Draws the head and neck ventrally when the limb is fixed.
+
**advances the limb and extends the shoulder joint when limb is in motion
 +
**draws head and neck ventrally when limb is fixed
  
−
'''''Omotransversarius''''':
+
'''''Omotransversarius''''': Accessory n.
−
:Innervated by: Accessory n.
+
*Origin: transverse processes of the atlas
−
:Origin: transverse processes of the atlas.
+
*Insertion: acromion and spine of scapula
−
:Insertion: acromion and spine of scapula.
+
*Action: advancing the limb
−
:Action: advancing the limb.
+
*Innervation
  
−
'''''Latissimus dorsi''''':
+
'''''Latissimus dorsi''''': local branch of brachial plexus
−
:Innervated by: local branch of brachial plexus
+
*The '''broadest muscle of the back'''
−
:The broadest muscle of the back.
+
*Origin: thoracolumbar fascia  
−
:Origin: thoracolumbar fascia.
+
*Insertion: teres tuberosity of the humerus
−
:Insertion: teres tuberosity of the humerus.
+
*Actions: antagonist to the brachiocephalic m.
−
:Actions: antagonist to the brachiocephalic m. The cranial fibers strap the scapula to the chest. It retracts the free limb and flexes shoulder joint. It draws the trunk forward over the fixed limb.
+
**cranial fibers strap scapula to the chest
 +
**retracts free limb and flexes shoulder joint
 +
**draws trunk forward over the fixed limb
  
−
'''''Pectoral mm.''''':
+
'''''Pectoral mm.''''': brachial plexus
−
:Innervated by: brachial plexus
+
*Two superficial parts, cranial and caudal, these aren't very distinct in the ox
−
:Two superficial parts, cranial and caudal, these aren't very distinct in the ox.
+
**Origin: cranial sternum
−
:Origin: cranial sternum.
+
**Insertion:
−
:Insertion:  
+
***cranial ('''descending'''): crest of the humerus distal to the deltoid tuberosity
−
::cranial ('''descending'''), crest of the humerus distal to the deltoid tuberosity.
+
***caudal ('''transverse'''): covers elbow joint to insert on the medial fascia of the forearm
−
::caudal ('''transverse'''): covers elbow joint to insert on the medial fascia of the forearm.
+
**Action: adduct the forelimb, assist in protraction and retraction
−
:Action: adduct the forelimb and assist in protraction and retraction.  
+
*One deep part ('''pectoralis profundus'''), with cranial and caudal parts
 +
**Origin: ventral sternum and adjacent cartilage
 +
**Insertions:
 +
***cranial (subclavius): supraspinatus m.
 +
***caudal (pectoralis ascendens): lesser tubercle of the humerus
 +
**Actions:
 +
***slinging trunk between forelimbs
 +
***may also retract free limbs
 +
***draw trunk forward when limb is fixed
  
−
'''''Serratis ventralis''''':
+
'''''Serratis ventralis''''': branch of brachial plexus
−
:Innervated by: branch of the brachial plexus.
+
*Origin: C4 to 10th rib
−
:Origin: C4 to 10th rib.
+
*Insertion: medial scapula and scapular cartilage
−
:Insertion: medial scapula and scapular cartilage.
+
*Action: supporting the weight of the trunk
−
:Action: supporting the weight of the trunk. It is reinforced by strong fascia. The cervical portion can retract the limb and the caudal portion can advance the limb.
+
**reinforced by strong fascia
 +
**cervical portion can retract the limb
 +
**caudal portion can advance the limb
  
−
'''''Rhomboids''''':
+
'''''Rhomboids''''': brachial plexus,
−
:Innervated by: brachial plexus
+
*Origin: nuchal ligament
−
:Origin: nuchal ligament.
+
*Insertion: dorsal border and adjacent scapula
−
:Insertion: dorsal border and adjacent scapula.
+
*Action: retracting the limb, may also raise limb
−
:Action: retracting the limb, may also raise the limb.
 
  
 
===Intrinsic Musculature===
 
===Intrinsic Musculature===
−
==Muscles of the Shoulder==
+
====Muscles of the Shoulder====
−
 
 
 
These muscles are grouped:
 
These muscles are grouped:
 +
*Lateral:'''Supraspinatus ''' and '''Infraspinatus''', Suprascapular n. of the brachial plexus
 +
**Origin: the fossae of the scapula
 +
**Insertion: both tubercles of the humerus
 +
**Action: brace the shoulder
 +
**Clinical significance: bursa between the tendon of the infraspinatus and lateral tubercle of the humerus can be the site of inflammation
 +
*Medial:
 +
**'''Supscapularis''': Subscapular n. from the brachial plexus
 +
***Origin: Deep surface of the scapula
 +
***Insertion: medial tubercle of the humerus
 +
***Action: braces medial shoulder joint, potential adductor
 +
**'''Coracobrachialis''': Musculocutaneous n. of the brachial plexus
 +
***Origin: medial supraglenoid tubercle
 +
***Insertion: proximal shaft of the humerus
 +
***Action: fixator
 +
*Caudal (Flexors): Axillary n. of the brachial plexus
 +
**'''Deltoids'''
 +
***Origin: caudal border and spine of the scapula, acromion
 +
****Two heads of origin
 +
***Insertion: deltoid tuberosity on the humerus
 +
**'''Teres Major'''
 +
***Origin: dorsal part of the caudal scapula
 +
***Insertion: teres tuberosity midway down humerus
 +
**'''Teres Minor'''
 +
*There are no defined extensors of the shoulder.  Those involved (brachiocephalic m., biceps brachii, supraspinatus, and ascending pectorals) have other, more primary roles.
  
−
===1. Lateral===
+
====Muscles of the Elbow====
−
 
+
''Extensors'': Radial n. from the brachial plexus
−
'''''Supraspinatus''''' and '''''Infraspinatus''''':  
+
*'''Triceps brachii''': Three heads,the medial branch is the most developed
−
:Innervated by: Suprascapular n. of the brachial plexus.
+
**Long head: caudal margin of the scapula
−
:Origin: the fossae of the scapula.
+
**Lateral, medial, and accessory heads: shaft of the humerus
−
:Insertion: both tubercles of the humerus.
+
**Insertion: olecranon, proteced by tricipital bursa against the bone and subcutaneous bursa against the skin
−
:Action: brace the shoulder.
+
*'''Tensor fasciae antebrachii'''
−
:Clinical significance: bursa between the tendon of the infraspinatus and lateral tubercle of the humerus can be the site of inflammation.
+
**Overlies triceps extending from scapula to olecranon
  
−
===2. Medial===
 
  
−
'''''Supscapularis''''':  
+
''Flexors'': Musculocutaneous n. from the brachial plexus
−
:Innervated by: Subscapular n. from the brachial plexus.
+
*'''Biceps brachii'''
−
:Origin: Deep surface of the scapula.
+
**Origin: supraglenoid tubercle of the scapula
−
:Insertion: medial tubercle of the humerus.
+
**Insertion: medial tuberosity of proximal radius and adjacent ulna
−
:Action: braces medial shoulder joint, potential adductor.
+
**Runs through the intertubercular groove of the humerus
 +
*'''Brachialis'''
 +
**Origin: proximocaudal humerus
 +
**Insertion: spirals to insert next to biceps
  
−
'''''Coracobrachialis''''':
 
−
:Innervated by: Musculocutaneous n. of the brachial plexus.
 
−
:Origin: medial supraglenoid tubercle.
 
−
:Insertion: proximal shaft of the humerus.
 
−
:Action: fixator.
 
  
−
===3. Caudal (Flexors)===  
+
====Muscles of the Carpal and Digital Joints====
 +
''Extensors'': Radial n. from the brachial plexus
 +
*Craniolateral position on the forearm
 +
*Almost all originate from the lateral epicondyle of the humerus
 +
*'''Extensor carpi radialis''': most medial, inserts on 2nd/3rd metacarpal bone
 +
*'''Ulnaris lateralis''': most lateral, inserts on accessory carpal bone
 +
*'''Extensor carpi obliquus''': aka '''abductor pollicis longus'''
 +
**Origin: cranial radius
 +
**Insertion: most medial metacarpal bone
 +
*Last two may also serve in medial deviation of the foot
 +
*'''Common Digital Extensor'''
 +
**Insertion: extensor process of the distal phalanx of each digit
 +
*'''Lateral Digital Extensor'''
 +
**Insertion: dorsal proximal phalanges
 +
*'''Medial Digital Extensor'''
 +
**Insertion: middle and distal phalanges
  
−
'''''Deltoids''''':
+
''Flexors'': Median or Ulnar n. of the brachial plexus
−
:Innervated by: Axillary n. of the brachial plexus.
+
*Caudal position on the forearm
−
:Origin: Two heads of origin; the caudal border and spine of the scapula and the acromion.
+
*Originate from the caudal medial epicondyle of the humerus
−
:Insertion: deltoid tuberosity on the humerus.
+
*'''Flexor carpi radialis''': most medial, inserts on upper 2nd/3rd metacarpal bone
−
:Action: Flexor of Shoulder.
+
*'''Flexor carpi ulnaris''': most lateral, inserts on the accessory carpal bone
 +
*'''Superficial Digital Flexor'''
 +
**Insertion: palmar surface of middle phalanges
 +
*'''Deep Digital Flexor'''
 +
**Passes through carpal canal before branching and continues to palmar distal phalanges
  
−
'''''Teres Major''''':
+
''Interosseus muscles''
−
:Innervated by: Axillary n. of the brachial plexus.
+
*This is covered in more detail in the [[Bovine Phalanges - Anatomy & Physiology|bovine phalanges]] section.
−
:Origin: dorsal part of the caudal scapula.
 
−
:Insertion: teres tuberosity midway down humerus.
 
−
 
 
−
'''''Teres Minor''''':
 
−
:Innervated by: Axillary n. of the brachial plexus.
 
−
 
 
−
 
 
−
 
 
−
There are no defined extensors of the shoulder. Those involved (brachiocephalic m., biceps brachii, supraspinatus, and ascending pectorals) have other, more primary roles.
 
−
 
 
−
 
 
−
 
 
−
==Muscles of the Elbow==
 
−
 
 
−
===Extensors===
 
−
 
 
−
'''''Triceps brachii''''':
 
−
:Innervated by: Radial n. from the brachial plexus
 
−
:Has three heads, the medial branch is the most developed. The long head is at the caudal margin of the scapula; The lateral, medial, and accessory heads are at the shaft of the humerus.
 
−
:Insertion: olecranon, proteced by tricipital bursa against the bone and subcutaneous bursa against the skin.
 
−
 
 
−
'''''Tensor fasciae antebrachii''''':
 
−
:Innervated by: Radial n. from the brachial plexus.
 
−
:Overlies the triceps extending from the scapula to the olecranon.
 
−
 
 
−
===Flexors===
 
−
 
 
−
'''''Biceps brachii''''':
 
−
:Innervated by:Musculocutaneous n. from the brachial plexus.
 
−
:Origin: supraglenoid tubercle of the scapula.
 
−
:Insertion: medial tuberosity of proximal radius and adjacent ulna. It runs through the intertubercular groove of the humerus.
 
−
 
 
−
'''''Brachialis''''':
 
−
:Innervated by: Musculocutaneous n. from the brachial plexus.
 
−
:Origin: proximocaudal humerus.
 
−
:Insertion: spirals to insert next to biceps.
 
−
 
 
−
==Muscles of the Carpal and Digital Joints==
 
−
 
 
−
===Extensors===
 
−
 
 
−
All have innervation from the radial n. from the brachial plexus. They have a craniolateral position on the forearm and almost all of them originate from the lateral epicondyle of the humerus.
 
−
 
 
−
'''''Extensor carpi radialis'''''
 
−
:The most medial, inserts on 2nd/3rd metacarpal bone.
 
−
 
−
'''''Ulnaris lateralis'''''
 
−
:The most lateral, inserts on accessory carpal bone.
 
−
 
 
−
'''''Extensor carpi obliquus''''' (aka- abductor pollicis longus)
 
−
:Origin: cranial radius.
 
−
:Insertion: most medial metacarpal bone .
 
−
 
 
−
'''''Common Digital Extensor'''''
 
−
:Insertion: extensor process of the distal phalanx of each digit.
 
−
 
 
−
'''''Lateral Digital Extensor'''''
 
−
:Insertion: dorsal proximal phalanges.
 
−
 
 
−
'''''Medial Digital Extensor'''''
 
−
:Insertion: middle and distal phalanges.
 
−
 
 
−
===Flexors===
 
−
 
 
−
All innervated by the median or ulnar n. of the brachial plexus. Have a caudal position on the forearm and originate from the caudal medial epicondyle of the humerus.
 
−
 
 
−
'''''Flexor carpi radialis'''''
 
−
:The most medial, inserts on upper 2nd/3rd metacarpal bone.
 
−
 
 
−
'''''Flexor carpi ulnaris'''''
 
−
:The most lateral, inserts on the accessory carpal bone.
 
−
 
 
−
'''''Superficial Digital Flexor'''''
 
−
:Insertion: palmar surface of middle phalanges.
 
−
 
 
−
'''''Deep Digital Flexor'''''
 
−
:Passes through carpal canal before branching and continues to palmar distal phalanges.
 
−
 
 
−
'''''Interosseus muscles'''''
 
−
:This is covered in more detail in the [[Bovine Lower Limb - Anatomy & Physiology|bovine lower limb]] section.
 
  
 
==Vasculature of the Forelimb==
 
==Vasculature of the Forelimb==
−
 
+
*'''[[Arteries of the Forelimb - Anatomy & Physiology|Arteries of the Forelimb]]'''
−
Click here for information on:
+
*'''[[Veins of the Forelimb - Anatomy & Physiology|Veins of the Forelimb]]'''
−
 
+
*'''[[Lymphatics of the Forelimb - Anatomy & Physiology|Lymphatics of the Forelimb]]'''
−
'''[[Arteries of the Forelimb - Anatomy & Physiology|Arteries of the Forelimb]]'''
 
−
 
 
−
'''[[Veins of the Forelimb - Anatomy & Physiology|Veins of the Forelimb]]'''
 
−
 
 
−
'''[[Lymphatics of the Forelimb - Anatomy & Physiology|Lymphatics of the Forelimb]]'''
 
−
 
 
−
 
 
−
==Webinars==
 
−
<rss max="10" highlight="bovine lameness arthritis feet">https://www.thewebinarvet.com/orthopaedics/webinars/feed</rss>
 
−
 
 
−
[[Category:Musculoskeletal System - Anatomy & Physiology]][[Category:Musculoskeletal Anatomy - Cattle]]
 
−
[[Category:A&P Done]]
 

Revision as of 14:20, 16 September 2008

Wiki.pngThis section has been fully reviewed, but still needs its pictures uploading.
Anatomy and PhysiologyWikiAnt and Phys Banner.png
()Map MUSCULOSKELETAL SYSTEM (Map)
FORELIMB



Structures of the Proximal Forelimb and Shoulder

Scapula

  • The ox possesses a small tuber scapular
  • It has acromion present
  • It has extensive scapular cartilage

Humerus

  • The humerus is essentially the same conformation as that of the dog.


Radius and Ulna

  • These are complete bones in the ox but are entirely fused
  • There is a proximal and distal interosseous space which are the only two places where the shafts are seperated
  • The ulna's proximal end is caudal to the radius and it's distal end forms the lateral styloid process, distal to the radius and articulating with the ulnar carpal bone.


Joints of the Proximal Forelimb

Shoulder Joint

  • The joint capsule attaches a very short distance from the periphery of the articular surfaces.
  • The intertubercular (bicipital) bursa lies between the humeral tubercles cushioning the bicipital tendon.
  • The bursa and tendon are held in place by the transverse humeral retinaculum running between the greater and lesser tubercles of the humerus.

Elbow Joint

  • The joint capsule attaches to the articular surface of the condyle, the periphery of the olecranon fossa and the articular cartilage of the trochlear notch of the ulna. It fuses with the collateral ligaments.
  • Paired collateral ligaments attach the epicondyles to the tuberosities of the radius and ulna.


Structures of the Distal Forelimb

Carpal bones

Carpal bones comprise two rows:

  • Proximally, (mediolaterally), radial, intermediate, ulnar and accessory bones
  • Distally, 1st is missing, 2 and 3 are fused

Metacarpal bones

These are covered in detail in the bovine phalanges section.


Joints of the Distal Forelimb

Carpal Joint

The carpal joint is a compound joint composed of:

  • The antebrachiocarpal joint between the radius/ulna and the proximal carpal bones
  • The middle carpal joint between the two rows of carpal bones
  • The carpometacarpal joint between the distal carpal bones and the proximal metacarpals

The joint is a synovial joint, comprised of a common outer fibrous capsule and three inner synovial pouches, one for each joint.

  • Collateral ligaments extend from the radius to the metacarpal bones on the medial and lateral aspect of the carpus.
  • The carpal canal houses both the deep digital flexor tendon and the deep branch of the superficial digital flexor.


Muscles of the Forelimb

Extrinsic Musculature

These muscle are responsible for joining the forelimb to the trunk, forming a synsarcosis rather than a conventional joint. Collectively, they act to transfer the weight of the body to the forelimbs as well as stabilize the scapula.

Trapezius: Accessory n.

  • Origin: mid-dorsal raphe and supraspinous ligament
  • Insertion: spine of the scapula
  • Body: two parts, cervical and thoracic separated by aponeurosis
  • Action: raises scapula against the trunk and swings cranially to advance the limb

Brachiocephalic m.: Accessory n.

  • Two parts separated by the clavicle where it exists
  • Origin: occipital bone, nuchal ligament, mastoid process
  • Insertion: deltoid tuberosity and fascia of limb
  • Actions:
    • advances the limb and extends the shoulder joint when limb is in motion
    • draws head and neck ventrally when limb is fixed

Omotransversarius: Accessory n.

  • Origin: transverse processes of the atlas
  • Insertion: acromion and spine of scapula
  • Action: advancing the limb
  • Innervation

Latissimus dorsi: local branch of brachial plexus

  • The broadest muscle of the back
  • Origin: thoracolumbar fascia
  • Insertion: teres tuberosity of the humerus
  • Actions: antagonist to the brachiocephalic m.
    • cranial fibers strap scapula to the chest
    • retracts free limb and flexes shoulder joint
    • draws trunk forward over the fixed limb

Pectoral mm.: brachial plexus

  • Two superficial parts, cranial and caudal, these aren't very distinct in the ox
    • Origin: cranial sternum
    • Insertion:
      • cranial (descending): crest of the humerus distal to the deltoid tuberosity
      • caudal (transverse): covers elbow joint to insert on the medial fascia of the forearm
    • Action: adduct the forelimb, assist in protraction and retraction
  • One deep part (pectoralis profundus), with cranial and caudal parts
    • Origin: ventral sternum and adjacent cartilage
    • Insertions:
      • cranial (subclavius): supraspinatus m.
      • caudal (pectoralis ascendens): lesser tubercle of the humerus
    • Actions:
      • slinging trunk between forelimbs
      • may also retract free limbs
      • draw trunk forward when limb is fixed

Serratis ventralis: branch of brachial plexus

  • Origin: C4 to 10th rib
  • Insertion: medial scapula and scapular cartilage
  • Action: supporting the weight of the trunk
    • reinforced by strong fascia
    • cervical portion can retract the limb
    • caudal portion can advance the limb

Rhomboids: brachial plexus,

  • Origin: nuchal ligament
  • Insertion: dorsal border and adjacent scapula
  • Action: retracting the limb, may also raise limb

Intrinsic Musculature

Muscles of the Shoulder

These muscles are grouped:

  • Lateral:Supraspinatus and Infraspinatus, Suprascapular n. of the brachial plexus
    • Origin: the fossae of the scapula
    • Insertion: both tubercles of the humerus
    • Action: brace the shoulder
    • Clinical significance: bursa between the tendon of the infraspinatus and lateral tubercle of the humerus can be the site of inflammation
  • Medial:
    • Supscapularis: Subscapular n. from the brachial plexus
      • Origin: Deep surface of the scapula
      • Insertion: medial tubercle of the humerus
      • Action: braces medial shoulder joint, potential adductor
    • Coracobrachialis: Musculocutaneous n. of the brachial plexus
      • Origin: medial supraglenoid tubercle
      • Insertion: proximal shaft of the humerus
      • Action: fixator
  • Caudal (Flexors): Axillary n. of the brachial plexus
    • Deltoids
      • Origin: caudal border and spine of the scapula, acromion
        • Two heads of origin
      • Insertion: deltoid tuberosity on the humerus
    • Teres Major
      • Origin: dorsal part of the caudal scapula
      • Insertion: teres tuberosity midway down humerus
    • Teres Minor
  • There are no defined extensors of the shoulder. Those involved (brachiocephalic m., biceps brachii, supraspinatus, and ascending pectorals) have other, more primary roles.

Muscles of the Elbow

Extensors: Radial n. from the brachial plexus

  • Triceps brachii: Three heads,the medial branch is the most developed
    • Long head: caudal margin of the scapula
    • Lateral, medial, and accessory heads: shaft of the humerus
    • Insertion: olecranon, proteced by tricipital bursa against the bone and subcutaneous bursa against the skin
  • Tensor fasciae antebrachii
    • Overlies triceps extending from scapula to olecranon


Flexors: Musculocutaneous n. from the brachial plexus

  • Biceps brachii
    • Origin: supraglenoid tubercle of the scapula
    • Insertion: medial tuberosity of proximal radius and adjacent ulna
    • Runs through the intertubercular groove of the humerus
  • Brachialis
    • Origin: proximocaudal humerus
    • Insertion: spirals to insert next to biceps


Muscles of the Carpal and Digital Joints

Extensors: Radial n. from the brachial plexus

  • Craniolateral position on the forearm
  • Almost all originate from the lateral epicondyle of the humerus
  • Extensor carpi radialis: most medial, inserts on 2nd/3rd metacarpal bone
  • Ulnaris lateralis: most lateral, inserts on accessory carpal bone
  • Extensor carpi obliquus: aka abductor pollicis longus
    • Origin: cranial radius
    • Insertion: most medial metacarpal bone
  • Last two may also serve in medial deviation of the foot
  • Common Digital Extensor
    • Insertion: extensor process of the distal phalanx of each digit
  • Lateral Digital Extensor
    • Insertion: dorsal proximal phalanges
  • Medial Digital Extensor
    • Insertion: middle and distal phalanges

Flexors: Median or Ulnar n. of the brachial plexus

  • Caudal position on the forearm
  • Originate from the caudal medial epicondyle of the humerus
  • Flexor carpi radialis: most medial, inserts on upper 2nd/3rd metacarpal bone
  • Flexor carpi ulnaris: most lateral, inserts on the accessory carpal bone
  • Superficial Digital Flexor
    • Insertion: palmar surface of middle phalanges
  • Deep Digital Flexor
    • Passes through carpal canal before branching and continues to palmar distal phalanges

Interosseus muscles

Vasculature of the Forelimb

Retrieved from "https://en.wikivet.net/index.php?title=Bovine_Forelimb_-_Anatomy_%26_Physiology&oldid=36710"