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Hindlimb - Anatomy & Physiology (view source)
Revision as of 14:11, 15 August 2008
, 14:11, 15 August 2008→Muscles of the Hindlimb
==Muscles of the Hindlimb==
==Muscles of the Hindlimb==
*'''[[Girdle Musculature - Anatomy & Physiology|Girdle Musculature]]'''
===Girdle Musculature===
*'''[[Rump Muscles - Anatomy & Physiology|Rump Muscles]]'''
*These muscles arise from the ventral aspect of the lumbar vertebrae and will insert on either the pelvis or femur. They are also known as the '''sublumbar muscles'''.
* Their main function is to:
** Stabilise the vertebral column and pelvis during locomotion.
** Control dorsiflexion and ventriflexion of the spine.
* The '''Psoas Minor'''
** Function: flexion of the vertebral column during the stance phase. Stabilisation of the vertebral column.
** Origin: 2nd-3rd caudal thoracic vertebrae on their ventral aspect and the 4th/5th cranial lumbar vertebrae
** Insertion: via a strong tendon to the psoas tubercle of the femoral shaft.
* The '''Iliopsoas''' - the strongest muscle of the girdle
** Function: Flexion of the hip and outward rotation of the stifle. ie. draws hindlimb forward
** In all animals, except carnivores were they are fused, the muscle can be divided into two distinct parts.
** The '''Greater Psoas''' - the lumbar portion.
*** Origin: last thoracic vertebrae and ribs and the bodies and transverse processes of the lumbar vertebrae.
*** Insertion: Incorporates with iliac muscle and inserts on the lesser trochanter.
*** It is positioned dorsally to the psoas minor and ventral to the quadrate lumbar muscle.
** The '''iliac muscle'''
*** Origin: wing and shaft of ilium
*** Insertion: via the common iliopsoas tendon to the lesser trochanter of the femur.
*** The muscle passes through the '''muscular lacuna'''; an opening between the os coxae laterally and caudally, the rectus abdominus medially and the iliac fascia cranially.
* The '''quadrate lumbar''' muscle
** Function: stabilisation of the lumbar vertebral column
** Origin: Ventral aspect of the transverse processes of the lumbar vertebrae and the proximal ends of the ribs
** Insertion: Ventral aspect of the wings of the ilium and sacrum.
===Rump Muscles===
The rump muscles main function is to extend the hip and some also extend the stifle and tarsus. They can be grouped into four distinct groups; the gluteals, the hamstrings, the medial muscles of the thigh and the inner pelvic muscles.
===='''The Gluteals'''====
They lie over the lateral and caudal aspect of the pelvic wall and extend between the thigh and ilium.
'''''Superficial Gluteal Muscle'''''
* This muscle shows great species variance and will be explained on their respective homepages.
* Function - Extension of the hip, also retraction of the limb and supports outward rotation.
'''''Gluteofemoral Muscle'''''
* This muscle only exists in the cat.
* Function - Retraction and abduction of the limb and hip extension
* Origin - 2nd-4th caudal vertebrae
* Insertion - Lateral aspect of patella and fascia lata via a aponeurosis
* Location - Between the superficial gluteal muscle and biceps muscle of the thigh.
'''''Middle Gluteal Muscle'''''
* This muscle also shows great species variance. Though all species have a superficial and deep portion that a seperated by a tendinous sheet. Both tendons on their site of insertion are protected by a synovial bursa.
* Function - most powerful extensor of the hip, also abducts and retracts the limb.
'''''Piriform Muscle'''''
* This is fused to the middle gluteal muscle except in carnivores.
* Function - Extensor of hip and abducter of the limb.
* Origin - last sacral vertebrae and sacrotuberous ligament.
* Insertion - just distal to the greater trochanter on the lateral aspect of the femur.
* Location - caudal and medial to the middle gluteal and is covered by the superficial gluteal.
'''Deep Gluteal Muscle'''
* Function - abduction of the limb.
* Origin - lateral aspect of the ilial shaft
* Insertion - via a short tendon to the greater trochanter.
'''''Tensor Muscle of the Fascia Lata'''''
* This muscle shows great species variance.
* Function - flexion of the hip and extension of the stifle.
===='''The Hamstrings'''====
These muscles cover the caudal aspect of the thigh and are multi-articular. They originate near the ischium and extend to the tibia and have some tendinous components that will make up the '''common calcanean tendon'''.
'''''Biceps Muscle of the thigh'''''
* The largest and most lateral of the muscles, it is superficial and covered only by fascia and skin.
* It consists of cranial part arising from the sacrum and sacrotuberous ligament and a small caudal part arising from the ischium.
* The muscle is composed of multiple parts and has different points of insertion in different species.
* Function - Extension and abduction of the limb. The cranial part extends the hip and stifle, though the caudal part extends the hip but flexes the stifle. It also causes tarsal extension.
* See species pages as is very species specific.
'''''Abductor muscle of the thigh'''''
* Only present in carnivores
* Function - abduction of the limb
* Origin - sacrotuberous ligament
* Insertion - crural fascia
'''''Semitendinous'''''
* Function - extends the hip, stifle and tarsus when the foot makes contact with the ground, therefore propulsing the animal. On a non-weightbearing leg it flexes the stifle and rotates the leg back and out.
* Origin - the ischial tuberosity ('''pelvic head''')
* Insertion - cranial margin of the tibia and a tendinous insertion on the calcaneal tuberosity.
'''''Semimembranous'''''
* The most medial of the hamstrings.
* Function - Extension of the hip and stifle in a weightbearing stance. On a non-weightbearing limb it adducts and retracts the limb.
* Origin - can be from either just the pelvic head or from the pelvic head and '''vertebral head'''. This is dependent on species.
* Insertion - onto the medial condyle of the femur and the medial condyle of the tibia.
===='''Medial Muscles of the Thigh'''====
This muscle groups main functions are to adduct the limb and to prevent unwanted abduction. They lie between the pelvic floor and the medial aspect of the femur.
'''''Sartorius'''''
* Function - flexion of the hip, advancement and abduction of the limb. It can also extend the hip via its attachments to the crural fascia and stifle fascia.
* Origin - Coxal tuberosity; ilial shaft or tendon of psoas minor
* Insertion - Deep fascia of the leg
* Location - superficially on the craniomedial border of the thigh as a strap like muscle.
'''''Gracilis'''''
* Function - adductor of the limb, extends the stifle.
* Origin - from an aponeurosis of the pelvic symphysis, the insertional tendons of the straight muscle of the abdomen. A tendinous plate is formed between the two aponeurosi of the gracilis' on which the adductor muscles originate.
* Insertion - An aponeurotic insertion with the crural fascia that attaches to the tibial crest.
* Location - broad muscular sheet on the caudal aspect of the medial part of the thigh.
'''''Pectineal Muscle'''''
* Function - flexor of the hip, adductor and supinator of the limb.
* Origin - iliopubic eminence of pelvic floor
* Insertion - medial border of the femur
* Location - a fusiform muscle extending between the pecten of the pubis, the pelvic floor and the femur.
'''''Adductor Muscles'''''
* Function - adduction of the limb, can also retract the limb
* Origin - the tendinous plate of the gracilis muscles.
* Insertion - medial aspect of the femur, fascia and ligaments of the medial aspect of the stifle.
===='''Inner Pelvic Muscles'''====
This set of muscles are a rather mixed group of small muscles lieing close to the hip joint. They lie between the pelvis and trochantic fossa of the femur.
'''''Internal Obturator'''''
* Only exists in carnivores and horses.
* Function - extension of the hip and rotation of the femur laterally.
* Origin and insertion - are both dependent on species involved.
'''''External Obturator'''''
* Function - supinator of the femur and adductor of the limb
* Origin - the ventral pelvic surface close to the obturator foramen
* Insertion - trochantic fossa
'''''Gemellus'''''
* Function - rotation of the limb laterally
* Origin - ischiatic spine
* Insertion - unites partially with the internal obturator and so inserts on the trochantic fossa.
'''''Quadrate Muscle'''''
* Function - extension of the hip and retraction of the limb
* Origin - ventral aspect of ischium
* Insertion - trochantic fossa
'''''Articular muscle of the hip joint'''''
* Only in carnivores and horses
* Function - causes tension of the joint capsule and thus helps prevent damage to the peri-articular structures.
* Origin - Hip joint capsule
*'''[[Muscles of the Stifle - Anatomy & Physiology|Muscles of the Stifle]]'''
*'''[[Muscles of the Stifle - Anatomy & Physiology|Muscles of the Stifle]]'''