Changes

==Common structures of the Proximal Forelimb and Shoulder==

 

==Common Structures of the Proximal Forelimb and Shoulder==

===Scapula===

===Scapula===

The Scapula forms the basis of the shoulder region, providing points of attachment of extrinsic and intrinsic muscles.  It is held in place by a synsarcosis of muscles and does not form a conventional articulation with the trunk. In ungulates, the dorsal border is extended by a scapular cartilage, which enlarges the area for muscle attachment.  This ossifies with age. The bone is roughly triangular, with a prominent '''spine''' that can be palpated through the skin.

The Scapula forms the basis of the shoulder region, providing points of attachment of extrinsic and intrinsic muscles.  It is held in place by a synsarcosis of muscles and does not form a conventional articulation with the trunk. In ungulates, the dorsal border is extended by a scapular cartilage, which enlarges the area for muscle attachment.  This ossifies with age. The bone is roughly triangular, with a prominent '''spine''' that can be palpated through the skin.

:The spine:

:The spine:

::defines '''Infraspinous''' and '''Supraspinous''' '''Fossae''', inhabited by muscles accordingly

::defines '''infraspinous''' and '''supraspinous''' '''fossae''', inhabited by the infraspinatus and supraspinatus muscles respectively

::serves as a point of attachment for the '''trapezius''' muscle

::serves as a point of attachment for the '''trapezius''' muscle

::culminates in the '''acromion''' in all but the horse and pig

::culminates in the '''acromion''' in all but the horse and pig.

 

Medial muscle attachment consist mostly of the '''subscapularis''', with the '''serratus ventralis''' attaching dorsally. The Scapula articulates with the humerus at the '''glenoid cavity'''.

Medial muscle attachment consist mostly of the '''subscapularis''', with the '''serratus ventralis''' attaching dorsally. The Scapula articulates with the humerus at the '''glenoid cavity'''.

===Humerus===

===Humerus===

The Humerus is the long bone of the forearm, articulating with the scapula to form the shoulder and the radius and ulna to form the elbow.  In situ, it lies obliquely along the ventral thorax and is more horizontal in larger species.   

The Humerus is the long bone of the arm, articulating with the scapula to form the shoulder and the radius and ulna to form the elbow.  In situ, it lies obliquely along the ventral thorax and is more horizontal in larger species.   

The head of the humerus comprises '''greater''' and '''lesser tubercles''', separated by an '''intertubercular groove''' through which runs the tendon of the '''biceps brachii'''. The shaft of the humerus takes on a characteristically twisted shape via a groove carrying the '''brachialis''' and '''radial nerve'''. Laterally, the '''deltoid tuberosity''' is palpable through the skin and connects to the head of the humerus via a ridge and merges distally with the '''crest of the humerus'''. Distally, the humerus culminates in a '''condyle''' which articulates to form the elbow.  

The head of the humerus comprises '''greater''' and '''lesser tubercles''', separated by an '''intertubercular groove''' through which runs the tendon of the '''biceps brachii'''. The shaft of the humerus takes on a characteristically twisted shape via a groove carrying the '''brachialis''' and '''radial nerve'''. Laterally, the '''deltoid tuberosity''' is palpable through the skin and connects to the head of the humerus via a ridge and merges distally with the '''crest of the humerus'''. Distally, the humerus culminates in a '''condyle''' which articulates to form the elbow.  

:In large animals, it meets the radius via a '''trochlea'''

:In large animals, it meets the radius via a '''trochlea'''

:In dogs and cats, it articulates with the radius medially via a trochlea and the ulna laterally via a '''capitulum'''

:In dogs and cats, it articulates with the ulna medially via a trochlea and the radius laterally via a '''capitulum'''

:Caudally, all species show an '''olecranon fossa''' which articulates with the '''olecranon''' of the ulna

:Caudally, all species show an '''olecranon fossa''' which articulates with the '''olecranon''' of the ulna

Medial and lateral epicondyles provide attachment for flexors and extensors of the carpus and digits.

Medial and lateral epicondyles provide attachment for flexors and extensors of the carpus and digits.

==Joints of the Proximal Forelimb==

==Joints of the Proximal Forelimb==

It is important to distinguish the shoulder/scapulohumeral joint from the entirely muscular connection (synsarcosis) between the forelimb and the trunk. This latter connection is sometimes called the '''girdle muscles''', although this is a problematic term, because many of its constituent muscles do not attach to a limb girdle muscle. At Cambridge University, it has for some time been given the name '''omothoracic junction''', but this term has not entered common usage.

It is important to distinguish the shoulder/scapulohumeral joint from the entirely muscular connection (synsarcosis) between the forelimb and the trunk. This latter connection is sometimes called the '''girdle muscles''', although this is a problematic term, because many of its constituent muscles do not attach to a limb girdle muscle. At Cambridge University, it has for some time been given the name '''omothoracic junction''', but this term has not entered common usage.

===Elbow Joint===

===Elbow Joint===

===Ulna===

===Ulna===

The Ulna's greatest contribution to functional anatomy is in the formation of the '''olecranon''', or the point of the elbow, which gives rise to the attachment of the '''triceps''' muscle.  The olecranon articulates with the humerus via its anconeal process. Distally (where unfused), the '''lateral styloid process''' articulates with the '''ulnar carpal bone'''.

The Ulna's greatest contribution to functional anatomy is in the formation of the '''olecranon''', or the point of the elbow, which gives rise to the attachment of the '''triceps''' muscle.  The olecranon articulates with the humerus via its anconeal process. The olecranon develops as an apophysis, i.e.. from a separate site of ossification. The trochlear notch on the cranial aspect of the ulna articulates with the large trochlea of the humerus which forms the main elbow joint capable of flexion and extension. Just distal to the trochlear notch, a large medial '''coronoid process''' and a smaller lateral coronoid process can be seen. Distally (where unfused), the '''lateral styloid process''' articulates with the '''ulnar carpal bone'''.

===Carpal bones===

===Carpal bones===

===Metacarpal Joint===

===Metacarpal Joint===

The metacarpal joint is defined by the presence of palmar [[Bones - Anatomy & Physiology#Types of Bone|'''sesamoids''']], which allow the flexor tendons to pass over the sharp change in angle presented by the joint. They are paired on each digit, with the exception of the first digit where it exists.

The metacarpal joint is defined by the presence of palmar [[Bones - Anatomy & Physiology#Types of Bone|'''sesamoids''']], which allow the flexor tendons to pass over the sharp change in angle presented by the joint. They are paired on each digit, with the exception of the first digit where only one exists. A single '''dorsal sesamoid bone''' can also be seen in dogs in digit 2 - 5 inclusive over the same joint between the metacarpal bone and the proximal phalanx. This is not found in ungulates or in the the first digit. However another sesamoid bone exists in the tendon of the abductor pollicis longus muscle of the first digit.

 

 

==Muscles of the Forelimb==

==Muscles of the Forelimb==

'''''Pectoral mm.''''':  

'''''Pectoral mm.''''':  

:Innervated by: brachial plexus

:Innervated by: brachial plexus

:Two superficial parts, cranial and caudal

:Two superficial parts, cranial and caudal

Medial:

Medial:

'''Supscapularis''':  

'''Subscapularis''':  

:Innervated by: Subscapular n. from the brachial plexus

:Innervated by: Subscapular n. from the brachial plexus

:Origin: Deep surface of the scapula

:Origin: Deep surface of the scapula

There are no defined extensors of the shoulder.  Those involved (brachiocephalic m., biceps brachii, supraspinatus, and ascending pectorals) have other, more primary roles.

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====

====Muscles of the Elbow====

==Species Specifics==

==Species Specifics==

===[[Canine Forelimb - Anatomy & Physiology|Canine Forelimb]]===

===[[Canine Forelimb - Anatomy & Physiology|Canine Forelimb]]===

===[[Bovine Forelimb - Anatomy & Physiology|Bovine Forelimb]]===

===[[Bovine Forelimb - Anatomy & Physiology|Bovine Forelimb]]===

[[Category:Musculoskeletal System - Anatomy & Physiology]]

[[Category:Musculoskeletal System - Anatomy & Physiology]]

[[Category:A&P Done]]

[[Category:A&P Done]]