Okay Anatomy Anatomy I: Lesson 13 - Imune...cranial aspect of the femur; it is covered by the: M. tensor fasciae latae, M. sartorius, Fascia lata and medial fascia of the thigh. •

Okay Anatomy

Anatomy I: Lesson 13

Myologia – Practical Tasks 15-18

Objective: Students will examine the practical dissection tasks 15-18 in order to prepare and succeed on the practical final exam.

B. Gerics

Practical Tasks:

• 15) medial muscles of the thigh, canalis

femoralis

• 16) m. quadriceps femoris, m. tensor

fasciae latae, m. sartorius

• 17) tarsal flexors

• 18) digital extensors of the hindlimb

Practical Task 15: Medial muscles of the thigh = Medial Thigh Muscles (hip joint)

• These muscles form a powerful group; they run strictly from the pelvis to the femur → acting mainly on the hip joint (→ inserting into crural fascia), partly also on the stifle.

• This group includes the following four (4) muscles:

1) M. sartorius : a narrow, strap-like muscle, lying superficially on medial aspect of the thigh (Evans p. 66/43) Origins:

– Ca (an man): coxal tuber – Su, Bo. Eq: border of ilium (Fascia

iliaca)

Insertion: fascia of the knee (Fascia cruris) Actions:

– flex hip joint – bring limb forewards and inwards – also to extend the stifle

c) Medial muscles of the thigh = Medial Thigh Muscles (hip joint)

2) M. gracilis : a broad muscular sheet, forming medial surface of the thigh, caudal to M. sartorius (p. 413/466 – 8; Evans p. 66/43) Origins:

– pelvic symphysis by means of an aponeurosis, and

– tendon of insertion of the M. rectus abdominis

Insertion: with a wide aponeurosis blending with crural fascia → inserting on tibial crest Actions: a powerful adductor,

– pulling the trunk sideways when limb is fixed

– also extends the stifle (by its connection with the fasciae of the crus and knee)


3) M. pectineus : a small but strong, spindle-shaped muscle, forming together with the M. gracilis the caudal boundary of the femoral canal.

Origins:

– pecten of pubis (Pecten ossis pubis) and

– iliopubic eminence

Insertion: labium medium of femur (Labium mediale of Facies aspera)

Actions:

– flex hip joint

– adduct and supinate the limb


4) Mm. adductores : consisting of three muscles (in man: four) which are variously fused with each other or with the M. pectineus; its shape being distinctly different among the sexes (Bo, Su). (Salomon p. 222/2.198-8; Evans p. 70/47)

Body: consisting of M. adductor -

– - longus, → as independent muscle only in the cat, in other species fused with pectineus

– - brevis, → separate only in Ca, Eq, but in Un → fused into: adductor magnus et brevis

– - magnus, → separate only in Ca, Eq, but in Un→ fused into: adductor magnus et brevis

– -minimus → in man


4) Mm. adductores : Origins: the whole group, ventrally from:

– pelvis and – either sides of the tendon of

origin (Tendo symphysialis) of M. gracilis

Insertions: facies aspera of femur Actions:

– adduct and draw limb limb backwards

– also: propel trunk forewards and sideways


Canalis femoralis (Schenkelspalt):

a deep groove on medial aspect of thigh, bounded cranially by M. sartorius and caudally by Mm. gracilis and pectineus. It is surrounded by the femoral fascia (Fascia femoralis medialis), and its depth is demarcated by the M. iliopsos and Mm. vastus medialis, vastus intermedius. The femoral canal contains normally:

• femoral artery and vein

• saphenous nerve

• first part of saphenous artery

• medial saphenous vein

In Eq also the deep inguineal lymph nodes are located here.

Practical Task 16:

• m. quadriceps femoris

• m. tensor fasciae latae

• m. sartorius

• 1) M. quadriceps femoris : powerful muscular complex lying on cranial aspect of the femur; it is covered by the: M. tensor fasciae latae, M. sartorius, Fascia lata and medial fascia of the thigh.

• (Evans p. 70/47)

• Body: consist of four (4) heads:

– M. vastus lateralis → covering cranilateral aspect of shaft of femur

– M. vastus medialis → applied to craniomedial aspect of shaft of femur

– M. vastus intermedius → between lateralis and medialis

– M. rectus femoris → strongest, covering the others cranially

• Origins:

– from the femur (the three vastus heads)

– from body of ilium (rectus femoris)

M. tensor fasciae latae : a strong, fan-shaped muscular pyramid between coxal tuber and stifle joint; it does not belong to the croup muscles but is included because of its origin and its main action into this group of muscles of the outer hip;

Origin: coxal tuber (of pelvis)

Insertions: distally forming a broad aponeurosis that blends with the fascia lata

– in Su, Bo, Eq: connected caudally with the M. glutaeus superficialis

Actions:

– flex hip joint

– draw limb forewards

– tense fascia lata → helps in extension of stifle joint

1) M. sartorius : a narrow, strap-like muscle, lying superficially on medial aspect of the thigh (Evans p. 66/43) Origins:

– Ca (an man): coxal tuber – Su, Bo. Eq: border of ilium (Fascia

iliaca)

Insertion: fascia of the knee (Fascia cruris) Actions:

– flex hip joint – bring limb forewards and inwards – also to extend the stifle


Practical Task 17: Tarsal Flexors

• a) Flexors of the hock joint These muscles are situated on the craniolateral aspect of the crus. They are long and spindle-shaped, and in Eq they may be entirely tendinous.

• They arise either on: the distal femur,

• or the proximal tibia and fibula,

• and end often in several branches on the distal part of the tarsus,

• or the proximal metatarsus

They include the following four (4) muscles:

** III. Muscles of the hock joint (hock joint)

• 1) M. tibialis cranialis : the most medial muscle in Eq (also in man), directly under crural fascia and skin; in other animals closely applied to the tibia. In Su, Bo, Eq: partly covered by M. fibularis tertius and M. digitorum longus. (Salomon p. 222/2.198/18; Evans p. 81/55).

• Origins:

– tibia – lateral condyle and crest

– also from fibula

• Insertions: tendon of insertion (with 2 branches in Eq) perforating the tendon of insertion of the M. fibularis tertius (M. peroneus tertius) to end medially on tarsal and metatarsal bones.

• Actions:

– flex hock joint

– supinate the foot


• 2) M. peronaeus (fibularis) tertius : absent in Ca, but fleshy in Bo, Su, purely tendinous in Eq;

• It blends more or less with the long digital extensor.

• Origin: extensor fossa of femur (together with the long digital extensor)

• Insertions: (with 2-3 branches in its tendon of insertion in Bo, Eq)

– distal tarsal bone, and

– proximal end of metatarsus

• Actions:

– flex hock joint

– in horse important part of the passive „stay apparatus“


• 3) M. peronaeus longus : narrow, spindle-shaped muscle on lateral aspect of crus; absent in Eq;

• Origins:

– proximal extremity of fibula

– lateral condyle of tibia

– lateral collateral ligament of stifle

• Insertions: (with long tendon of insertion running over lateral side of hock-joint, turning then to the plantar surface) and inserting medially on T1, T2 or Mt1

• Actions:

– assist in flexion of the hock-joint, and

– pronate the foot (esp. in Ca)


• 4) M. peronaeus brevis : only (recognizable) in man and Ca; a very weak muscle

• Origin: the fibula below M. fibularis longus and M. extensor digitorum lateralis

• Insertions: (its long, thin tendon of insertion passes over the hock-joint) to be attached to Mt5

• Actions: flex hock joint

A. Long muscles of the digits • 1) M. extensor digitorum longus :

situated between the cranial tibial and the lateral extensor of the digits, with differences between species; partly or extensively fused with M. peroneus tertius. Their (joint terminal) tendon runs over dorsal surface of the hock-joint, then dividing differently in different mammals. (plate VII./460-463/7-7'; Evans p. 80/54; p. 81/55)

• Origins: extensor fossa of femur (together with M. peroneus tertius → the 2 muscles extensively fused)

A. Long muscles of the digits

• Insertions:

– Ca (and man): four (4) branches of the tendon → to distal phalanx of digits 2nd – 5th

– Su: (3 bellies: middle-, medial-, lateral-)

• middle → 3rd and 4th digits

• medial → 3rd digit: middle and distal phalanges

• lateral → 2nd, 4th and 5th digits

– Bo: largely fused with M. peroneus tertius (2 bellies: medial- and lateral-)

• medial → 3rd digit: distal phalanx

• lateral → split into two (2) branches → 3rd and 4th digits: distal phalanx

– Eq: (uniform muscle) → 3rd digit: distal phalanx

1) M. extensor digitorum longus


• Actions:

– extend the digits

– draw the foot forewards


A. Long muscles of the digits • 3) M. extensor hallucis longus : = long

extensor of the first digit; present as an individual muscle only on Ca, Su, sheep (and man); in the other animals it has fused with the M. cranialis tibialis. (Evans p. 80/54).

• Origin: middle part of fibula (beside or beneath the cranial tibial)

• Insertions: → 1st digit: distal phalanx (in man)

– in domestic mammals, (excl. sheep) → 2nd digit: proximal phalanx, and

• → rudiment of 1st digit, or even

• 2nd Mt

• Actions: extend the 2nd or 1st digit

Practical Task 18: Digital Extensors of hind limb


The sitation, arrangement and function of the digits of the pelvic limb is basically similar to those of the thoracic limbs. However, there are only four digits left in the pelvic limbs (the 1st digit is absent in all domestic mammals except dog).

As in the thoracic limbs the muscles of the pelvic limbs can also be subdivided into „long“ and „short“ muscles. We will deal only with the „long“ muscles.


a) Long digital extensors

• Their muscle bellies are craniolaterally on the crus.

• They are closely associated with the M. peroneus (fibularis) tertius.

• They arise either from the femur or the two crural bones (tibia/fibula).

• Their tendons of insertion split into a number of branches (depending in the number of digits), and some of these branches link up again.

• They end dorsally on the phalanges

– or as secondary attachments on the metatarsus

They include the following three (3) muscles:

A. Long muscles of the digits • 1) M. extensor digitorum longus :

situated between the cranial tibial and the lateral extensor of the digits, with differences between species; partly or extensively fused with M. peroneus tertius. Their (joint terminal) tendon runs over dorsal surface of the hock-joint, then dividing differently in different mammals. (plate VII./460-463/7-7'; Evans p. 80/54; p. 81/55)

• Origins: extensor fossa of femur (together with M. peroneus tertius → the 2 muscles extensively fused)


• Insertions:

– Ca (and man): four (4) branches of the tendon → to distal phalanx of digits 2nd – 5th

– Su: (3 bellies: middle-, medial-, lateral-)

• middle → 3rd and 4th digits

• medial → 3rd digit: middle and distal phalanges

• lateral → 2nd, 4th and 5th digits

– Bo: largely fused with M. peroneus tertius (2 bellies: medial- and lateral-)

• medial → 3rd digit: distal phalanx

• lateral → split into two (2) branches → 3rd and 4th digits: distal phalanx

– Eq: (uniform muscle) → 3rd digit: distal phalanx



• Actions:

– extend the digits

– draw the foot forewards


A. Long muscles of the digits 2) M. extensor digitorum lateralis : lies on lateral aspect of the crus under the M. peroneus longus (in Ca/dog); and behind it in Su and Bo; in Eq it is related to the M. extensor digitorum longus. Its tendon of insertion passes over the tarsal bones, blending with the (terminal tendon) of the M. extensor digitorum longus.

(plate VII./460-463/10) . In Su it has two (2) bellies (plate VII./460-463/10'-10'').

• Origins:

– fibula

– lateral collateral ligament of stifle joint


• Insertions: differences between different species:

– Ca: → 5th digit: first phalanx

– Su: → splitting into two: → 4th and 5th digits

– Bo: → 4th digit: middle phalanx

– Eq: → blending with terminal tendon of M. extensor digitorum longus

• Actions: extend the relevant digits

2) M. extensor digitorum lateralis

A. Long muscles of the digits • 3) M. extensor hallucis longus : = long

extensor of the first digit; present as an individual muscle only on Ca, Su, sheep (and man); in the other animals it has fused with the M. cranialis tibialis. (Evans p. 80/54).

• Origin: middle part of fibula (beside or beneath the cranial tibial)

• Insertions: → 1st digit: distal phalanx (in man)

– in domestic mammals, (excl. sheep) → 2nd digit: proximal phalanx, and

• → rudiment of 1st digit, or even

• 2nd Mt

• Actions: extend the 2nd or 1st digit

Documents

Okay Anatomy Anatomy I: Lesson 13 - Imune...cranial aspect of the femur; it is covered by the: M. tensor fasciae latae, M. sartorius, Fascia lata and medial fascia of the thigh. •