Lab 8 – Review Lab

Lab instructions:

Use this lab to review the integument and thoracic limb content.  Plan to be prepared for the lab and to focus on topics or specific structures that you/your dissection team, wish to gain more understanding of, particularly with the assistance of instructors.  Below, we have provided the list of links to lab review videos and a compilation of the terms lists, for the thoracic limb section.

When you have completed your review, try your hand at the clinical application questions, practice exam questions, and interactive review questions. Then view the “Tips for your first practical exam” page.

Review Videos

Osteology:

Carnivore Thoracic Limb Regions and Bones – 6 minutes

Carnivore Thoracic Limb Osteology – 12 minutes

Horse Thoracic Limb Osteology -22 minutes

Cow Thoracic Limb Osteology – 11 minutes

Horse and ruminant Thoracic Limb Ligaments – 17 minutes

 

Extrinsic Muscles:

Dog Extrinsic Thoracic Limb Muscles – Watch until 11 minutes

Cat Extrinsic Thoracic Limb Muscles – Watch until 4 minutes

Horse Extrinsic Thoracic Limb Muscles – Watch until 5:45

Calf Extrinsic Thoracic Limb Muscles – Watch until 11:40

Goat Extrinsic Thoracic Limb Muscles – Watch until 5:30

Pig Extrinsic Thoracic Limb Muscles – Watch until 3:40

 

Intrinsic Muscles – Brachium

Dog Brachial Muscles – 6 minutes

Cat Brachial Muscles – Watch until 7:30

Horse Brachial Muscles – 9 minutes (watch until 9 minutes)

Calf Brachial Muscles – 4 minutes (watch until 4 minutes)

Goat Brachial Muscles – 6 minutes (watch until 6:30)

Pig Brachial Muscles – 3:30 minutes

 

Intrinsic Muscles – Antebrachium

Dog Antebrachial Muscles – 8 minutes

Cat Antebrachial Muscles – 4 minutes

Horse Antebrachial Muscles – 12 minutes

Calf Antebrachial Muscles – 4 minutes

Goat Antebrachial Muscles – 7 minutes

 

Ungulate Highlights:

Horse Thoracic Limb – 22 minutes

Calf Thoracic Limb – 8 minutes

Goat Thoracic Limb – 14 minutes

Pig Thoracic Limb – 3 minutes

Horse and ruminant Thoracic Limb Ligaments and Structures – 17 minutes

 

Interactive Review Content: 

Horse injury terms

 

Muscles, structures, terms – all of Thoracic Limb

Print optimized terms list

Lab 1:

Regions of the thoracic limb (proximal to distal) Bones of the region
 Common Name Species
Withers Highest point of spinous processes of thoracic vertebrae Horse
Shoulder Scapula All
Brachium Humerus Arm All
Antebrachium Radius, ulna Forearm All
Manus Bones of carpus, metacarpus, digits All
Carpus Carpal bones ‘Knee’ – particularly in horse All
Metacarpus Metacarpal bones ‘Cannon’ – ungulate All
Digit Phalanges (proximal, middle, distal) In ungulates, includes pastern and “foot” All
Pastern Proximal and middle phalanges Ungulates
Foot Distal phalanx Hoof Ungulates
Joints of the thoracic limb (proximal to distal) Common Name
Scapulohumeral or glenohumeral joint Shoulder
Cubital joint Elbow
Carpus “Knee” in horse
antebrachiocarpal joint
middle carpal joint
carpometacarpal joint
Metacarpophalangeal joint Fetlock, Ankle (ungulates)
Proximal interphalangeal joint Pastern joint – ungulates
Distal interphalangeal joint Coffin joint – ungulates


Osteology of Shoulder and Brachium
Osteology Features Species differences/comments
Scapula Scapular spine
Acromion Two parts in cat; acromion not present in horse and pig
Supraspinous fossa
Infraspinous fossa
Subscapular fossa
Supraglenoid tubercle
Serrated face
Glenoid cavity
Neck of scapula
Scapular cartilage (attached at dorsal margin of scapula) Ungulate
Clavicle Near point of shoulder. Dog – a fibrous clavicular intersection; Cat – has bony clavicle
Humerus Head of humerus
Greater tubercle Horse – cranial and caudal parts
Lesser tubercle
Intermediate tubercle Horse
Intertubercular (bicipital) groove
Neck of humerus
Shaft or body of humerus
Deltoid tuberosity
Teres major tuberosity
Teres minor tuberosity
Lateral supracondylar crest
Lateral/medial epicondyles
Humeral condyle
Supratrochlear foramen Dog
Supracondylar foramen Cat

 


Osteology of Antebrachium
Osteology Features Species differences/comments
Radius Head of radius
Radial tuberosity
Shaft or body of radius
Medial styloid process
Ulna Olecranon of ulna/tuber olecrani/olecranon  tuberosity
Trochlear notch
Anconeal process
Medial and lateral coronoid process
Ulnar tuberosity
Lateral styloid process Fused to radius in horse

Osteology of Carpus
Osteology Species differences/comments
Intermedioradial carpal bone Carnivore only (= fused intermediate and radial carpal bones)
Radial carpal bone Ungulate only
Intermediate carpal bone Ungulate only
Ulnar carpal bone
Accessory carpal bone projects palmarly as very palpable prominence
Carpal bones I, II, III, IV Carnivore – 1, 2, 3, 4

Pig – 1, 2, 3, 4

Ruminant – Fused 2/3, 4

Horse – [inconsistent 1], 2, 3, 4
Sesamoid in abductor pollicis longus Carnivore

Osteology of Metacarpus and Digit
Osteology Features Species differences/comments
Metacarpal bones Base (proximal end); Head (distal end)
Metacarpal bone I Carnivore only
Metacarpal bone II Horse – “button” of splint bone at distal end Horse – MC2 is the medial splint bone
Metacarpal bone III

aka Cannon bone of ungulates

 Sagittal ridge of MC3 Horse
Metacarpal tuberosity Ungulate – Insertion of ECR m.

Ruminant – MC3+MC4 fused
Metacarpal bone IV Horse – “button” of splint bone at distal end Horse – MC4 is the lateral splint bone

Ruminant – MC3+MC4 fused
Metacarpal bone V Carnivore present, and ruminant – vestigially present
Proximal sesamoid bones ‘Base’, ‘apex’, axial and abaxial surfaces Ungulate only; at level of palmar side of metacarpophalangeal joint
Dorsal sesamoid bones Carnivore only
Distal sesamoid/Navicular bone proximal border, distal border, flexor and articular surfaces, sagittal ridge of navicular bone Ungulate at level of palmar distal interphalangeal joint.
Digits I-V – species variation Consist of proximal, middle and distal phalanges; axial and abaxial side to each digit (or medial and lateral sides in horse since only one digit) Carnivores – 5 digits (2-5 are weight bearing)

Ruminant and Pig – 4 digits (3 and 4 are weight bearing; 2 and 5 = dewclaws)

Horse – 1 digit (3rd digit, bears all weight of limb!)
Proximal phalanx Base (proximal end); Head (distal end) Ungulate – Pp, P1, long pastern bone
Middle phalanx Base (proximal end); Head (distal end) Ungulate – Pm, P2, short pastern bone

Carnivore – Pm is absent in digit 1.
Distal phalanx Ungulate – Pd, P3, coffin or pedal bone
Extensor process All (attachment of CDE)
Flexor tubercle of Pd Carnivore, Ruminant
Solar border (margin) Horse
Crena marginis solearis Horse
Medial and lateral palmar processes (‘wings’) of Pd Horse
Solar surface Horse (DDFT attaches to solar surface)

Ligaments related to bones and joints of the thoracic limb
Landmarks Species differences/comments
Transverse humeral retinaculum Carnivore
Medial/lateral collateral ligaments of elbow
Medial/lateral collateral ligaments of carpus
Elastic dorsal ligaments – know concept Cat
Palmar (inter)sesamoidean ligament Horse
Straight sesamoidean ligament Horse – superficial, Y
Oblique sesamoidean ligament Horse – middle, V
Cruciate sesamoidean ligament Horse – deep, X
Collateral sesamoidean ligaments Horse – proximal sesamoids to MC3 and Pp
Collateral (suspensory) ligg. of navicular bone Horse
Distal navicular (impar) ligament Horse
Proximal and distal interdigital ligaments Ruminant

Lab 3: Extrinsic Thoracic Limb muscles and structures

Muscle/structure

Muscle attachments/comments

Muscle actions/comments
CUTANEUS TRUNCI M.
  1. Superficial fascia of the trunk and skin
 Twitches skin
SUPERFICIAL PECTORAL M.
  1. Cranial sternum (1st-3rd sternebrae)
  2. Proximal cranial humerus (Crest of greater tubercle)
  • Cat difference: limb attachment is on proximal ulna.
 Adduct limb
DEEP PECTORAL M.
  1. Ventral sternum
  2. Lesser and greater tubercles (of humerus)
 Adduct limb
BRACHIOCEPHALICUS M.
  1. Clavicular intersection
  2. Cranial midline neck and temporal bone (mastoid process).
  3. Cranial, distal humerus
  • Cat difference: limb attachment on proximal ulna.
 Extend shoulder joint; draw head and neck to the side
Clavicular intersection/clavicle in cat The ‘center’ of the brachiocephalicus m.  from which parts are named. Note in carnivores only.
OMOTRANSVERSARIUS M.
  1. Wing of atlas (C1 vertebra)
  2. Acromion of scapula and scapular spine
 Advance the limb; flex neck laterally
TRAPEZIUS M.
  1. Dorsal midline – neck to cranial thorax
  2. Scapular spine
 Draw scapula dorsally (elevate scapula/limb)
RHOMBOIDEUS M.
  1. Skull, and dorsal midline – neck to cranial thorax
  2. Dorsal border of scapula
 Draw scapula dorsally

(elevate scapula/limb)
LATISSIMUS DORSI M.
  1. Thoracolumbar fascia
  2. Teres major tuberosity (of humerus)
 Flex shoulder joint; draw free limb caudally, as in digging action.
SERRATUS VENTRALIS M.
  1. Cervical vertebrae and ribs
  2. Serrated face of scapula
 Support the trunk
STERNOCEPHALICUS M.
  1. 1st sternebra (aka manubrium)
  2. Occipital bone and mastoid process of temporal bone
 To draw the head and neck to the side
STERNOHYOIDEUS M.
  1. 1st sternebra & 1st costal cartilage
  2. Hyoid apparatus
 Pull tongue & larynx caudally
STERNOTHYROIDEUS M.
  1. 1st costal cartilage
  2. Thyroid cartilage of larynx
 Pull tongue & larynx caudally
OMOHYOIDEUS M.

Note in horse only; no need to know attachments

 ‘Backstop muscle’ of jugular groove in cranial neck.
CUTANEUS COLLI M.

Note in horse only; no need to know attachments

 Covers external jugular v. in caudal neck.
SUBCLAVIUS M.

Horse, pig – no need to know attachments.

 Extra pectoral muscle.
Superficial thoracic v.

Horse only feature.

 

Lab 4: Intrinsic muscles of shoulder and brachium

Muscle Action Groups
Extensors of the shoulder
  • Supraspinatus
  • Infraspinatus
  • Subscapularis
Flexors of the shoulder
  • Deltoideus
  • Teres minor
  • Teres major
Extensors of the elbow
  • Tensor fasciae antebrachii
  • Triceps brachii
Flexors of the elbow
  • Biceps brachii
  • Brachialis
  • Brachioradialis (cat, next lab)

Muscle/structure

 

Attachments/comments

 

Action/comments

 
SUPRASPINATUS M.
  1. Supraspinous fossa
  2. Greater and lesser tubercle (of humerus) – species variation
 Extend shoulder joint/shoulder stabilization
INFRASPINATUS M.
  1. Infraspinous fossa
  2. Greater tubercle (of humerus) – lateral aspect
 Extend shoulder joint/shoulder stabilization
Infraspinatus m. bursa

Deep to superficial tendon of m. ie it is a subtendinous bursa

 Protect tendon as passing over bone
SUBSCAPULARIS M.
  1. Subscapular fossa
  2. Lesser tubercle (of humerus)
 Extend shoulder joint/shoulder stabilization
DELTOIDEUS M.
  1. Scapula (acromion and spine) – species variation.
  2. Deltoid tuberosity (of humerus)
 Flex shoulder joint
TERES MINOR M.
  1. Caudal border of scapula (distal)
  2. Teres minor tuberosity of humerus
 Flex shoulder joint; rotate shoulder laterally
TERES MAJOR M.
  1. Caudal border of scapula (proximal)
  2. Teres major tuberosity (of humerus)
 Flex shoulder joint
TENSOR FASCIAE ANTEBRACHII M.
  1. Fascia covering latissimus dorsi m.
  2. Olecranon of ulna
 Extend elbow joint (weak)
TRICEPS BRACHII M. (LONG HEAD)
  1. Caudal border of scapula
  2. Olecranon of ulna
 Extend elbow joint (secondary: flex shoulder joint)
TRICEPS BRACHII M. (LATERAL HEAD)
  1. Proximal lateral humerus
  2. Olecranon of ulna
 Extend elbow joint
TRICEPS BRACHII M. (ACCESSORY HEAD)
  1. Neck of the humerus
  2. Olecranon of ulna
 Extend elbow joint
TRICEPS BRACHII M. (MEDIAL HEAD)
  1. Proximal medial humerus
  2. Olecranon of ulna
 Extend elbow joint
BICEPS BRACHII M.
  1. Supraglenoid tubercle
  2. Ulnar and radial tuberosities – species variation
 Flex elbow joint (secondary: extend shoulder joint)
Intertubercular (bicipital) bursa

Horse and ruminant structure

 Protects tendon passing over point of shoulder
Lacertus fibrosus

Horse; long tendon of insertion of biceps into Extensor Carpi Radialis m.
BRACHIALIS M.
  1. Proximal lateral humerus
  2. Ulnar and radial tuberosities – species variation
 Flex elbow joint

 

Lab 5: Intrinsic Thoracic Limb mm. – antebrachium

 

Muscle Action Groups
Extensors of carpus and digits
  • Extensor carpi radialis
  • Common digital extensor
  • Lateral digital extensor
  • Abductor digiti I longus
Flexors of carpus and digits
  • Ulnaris lateralis
  • Flexor carpi radialis
  • Superficial digital flexor
  • Deep digital flexor
  • Flexor carpi ulnaris
Supinators
  • Brachioradialis (cat)
  • Supinator
Pronators
  • Pronator teres
  • Pronator quadratus

Muscle/structure

Attachments/comments

Action/comments
EXTENSOR CARPI RADIALIS M.
  1. Lateral supracondylar crest of the humerus
  2. Dorsal base of metacarpal(s) – species variation
 Extend carpus
COMMON DIGITAL EXTENSOR M.
  1. Lateral epicondyle of the humerus
  2. Extensor process of the distal phalanges – species variation.
 Extend digits and carpus
LATERAL DIGITAL EXTENSOR M.
  1. Lateral epicondyle of the humerus – carnivores
    Proximal radius and ulna – ungulates
  2. Dorsal base (ie proximal end) of phalanges – species variation
 Extend digits and carpus
ABDUCTOR DIGITI I LONGUS M.(ABDUCTOR POLLICIS LONGUS)
  1. Craniolateral ulna
  2. Base of medial metacarpus – species variation
 Abduct first digit (as exists) and extend carpus
Extensor retinaculum Fibrous band of thickened fascia at level of dorsal carpus Binds down extensor tendons
ULNARIS LATERALIS M.
  1. Lateral epicondyle of the humerus
  2. Base of lateral metacarpus – species variation
 Flex carpus; abduct manus at carpus
Ulnaris lateralis bursa Synovial ‘cushion’ deep to proximal tendon of origin Horse
FLEXOR CARPI RADIALIS M.
  1. Medial epicondyle of the humerus and medial radius
  2. Palmar base of metacarpals – species variation
 Flex carpus
SUPERFICIAL DIGITAL FLEXOR M.
  1. Medial epicondyle of the humerus
  2. Palmar base of middle phalanges (plus proximal phalanx in horse)
  • Note, two bellies in ruminant.
 Flex proximal interphalangeal joints; flex carpus and metacarpophalangeal joints)
Accessory ligament of SDF aka proximal or superior check ligament Horse
DEEP DIGITAL FLEXOR M.

(Humeral, Ulnar, Radial heads)
  1. Medial epicondyle of the humerus, caudal ulna, medial radius
  2. Flexor tubercle of distal phalanges (solar surface in horse)
 Flex digits and carpus
Accessory ligament of DDF aka distal or inferior check ligament Horse
Flexor retinaculum Fibrous band with superficial and deep parts on the palmaromedial carpus Binds digital flexors within carpal canal
FLEXOR CARPI ULNARIS M. (Humeral and Ulnar heads)
  1. Medial epicondyle of humerus, and olecranon
  2. Accessory carpal bone
 Flex carpus
BRACHIORADIALIS M

(Cat Only; Vestigial, but frequently seen, in Dog)
  1. Lateral distal humerus
  2. Distal radius
 Supination
SUPINATOR M.
  1. Lateral epicondyle of the humerus
  2. Cranial, proximal radius
 Supination of distal limb (and flex elbow)
PRONATOR TERES M.
  1. Medial epicondyle of the humerus
  2. Medial border of proximal mid radius
 Pronation of the distal limb (and flex elbow)
PRONATOR QUADRATUS M.
  1. Apposed surfaces of the radius and  ulna
 Pronation of the distal limb
Synovial tendon sheaths Surround tendons of muscles passing over joints Also to view in next lab

Lab 7: Ungulate distal limb

Note, a number of these terms have been introduced in previous labs.

Structure/feature Comments/species specific
Ligament of ergot Horse – if remains visible after skin reflection
Lateral and medial collateral ligaments of carpus
Carpal canal Bound by 3 structures
Flexor retinaculum
Palmar carpal ligament
Accessory carpal bone
Carpal sheath Synovial sheath wrapped around flexor tendons in carpal canal.
Dorsal metacarpal ligament Horse
Common digital extensor tendon(s) Two tendons present in ruminant
Lateral digital extensor tendon
Tendon sheath
Suspensory ligament Recall, fused 3rd and 4th interossei in ruminant.
Superficial digital flexor tendon Two tendons in ruminant
Deep digital flexor tendon
Accessory ligament of DDFT = distal check ligament Horse
Dorsal pouch fetlock joint Horse
Synovial fold Horse – within dorsal pouch of fetlock joint
Palmar pouch of fetlock joint Horse
Digital flexor tendon sheath Horse
Manica flexoria Horse – part of SDFT surrounding DDFT
Palmar (inter)sesamoidean ligament Horse
Palmar annular ligament
Proximal digital annular ligament Horse
Distal digital annular ligament Horse
Dtraight sesamoidean ligament Horse
Cruciate sesamoidean ligament Horse
Oblique sesamoidean ligament Horse – model
Short sesamoidean ligament Horse – model
Distal navicular ligament = impar ligament Horse
Collateral (suspensory) ligaments of navicular bone Horse
Navicular bursa Horse
Proximal interdigital ligament Ox
Distal interdigital ligament Ox

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Unit 2: Musculoskeletal System Copyright © by Mathew Gerard and Lindsey Cobb. All Rights Reserved.

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