Anatomy of the Canine Front Limb: Difference between revisions

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* There are no other ligaments
* There are no other ligaments
* The synovial sheath of the biceps brachii tendon is an extension of the joint capsule
* The synovial sheath of the biceps brachii tendon is an extension of the joint capsule
{{#ev:youtube|En4dLdmR4O8}}<ref>Priya Streram. *LEARN* Applied Anatomy of the Canine Shoulder. Available from https://www.youtube.com/watch?v=En4dLdmR4O8 [last accessed 28/2/21]</ref>
{{#ev:youtube|En4dLdmR4O8}}<ref>Priya Streram. *LEARN* Applied Anatomy of the Canine Shoulder. Available from https://www.youtube.com/watch?v=En4dLdmR4O8 [last accessed 28/2/21]</ref>


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** Medial and lateral collateral ligaments. These limit rotation when the elbow is flexed
** Medial and lateral collateral ligaments. These limit rotation when the elbow is flexed
** Annular ligament of the radial head
** Annular ligament of the radial head
=== Distal Radial-Ulnar Joint<ref name=":0" /> ===
* Part of the antebrachiocarpal joint (shares a joint capsule)
==== Elbow Joint Range of Motion and Ranges<ref name=":0" /> ====
{| class="wikitable"
{| class="wikitable"
!Joint
!Joint
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|
|
|Extension
|Extension
|170
|170 degrees
|-
|-
|
|
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|Radioulnar
|Radioulnar
|Pronation
|Pronation
|40-50
|40-50 degrees
|-
|-
|
|
|Supination
|Supination
|80-90
|80-90 degrees
|}
 
=== Carpal Joint<ref name=":0" /> ===
* Hinge joint
* Radiocarpal (RC) - consists of the trochlear of the radius and carpals
* Midcarpals (MC) - proximal and distal carpals
* Carpometacarpals (CMCs) - carpal bones (II-IV) and metacarpals (II to IV)
* Intercarpals (IC) - carpals of the same row
* Ligaments of the carpal joint
** Medial and lateral collateral ligaments
** Intercarpals
** Palmar carpal ligament (fibrocartilage)
** Flexor retinaculum
* Carpal canal
** Formed by the accessory carpal bone (laterally), the palmar carpal ligament (cranially) and the flexor retinaculum (palmar)
** Structures passing through the carpal tunnel include:
*** Tendons and synovial sheaths of the superficial and deep digital flexor tendons
*** Ulnar and median nerves
*** Arteries and veins
 
==== Carpus Joint Range of Motion and Ranges<ref name=":0" /> ====
{| class="wikitable"
!Joint
!Movement
!Normal ROM for Dogs
|-
|Carpus
|Flexion
|20-30 degrees
|-
|
|Hyper-extension
|10-15 degrees
|-
|
|Radial or medial deviation
|15-20 degrees
|-
|
|Ulnar or lateral deviation
|15-20 degrees
|}
|}


== References ==
== References ==
<references />
<references />

Revision as of 09:29, 28 February 2021

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This page introduces the anatomy of the canine front limb, also known as forelimb and thoracic limb.

Skeletal System[edit | edit source]

The bones of the front limb are:

  • Scapula
  • Humerus
  • Radius
  • Ulnar
  • Carpus
  • Metacarpals
  • Phalanges

Specific Features of the Canine Skeleton[1][edit | edit source]

  • While dogs do have a clavicle, it is a rudimentary structure within the brachiocephalicus muscle and it is rarely seen on x-ray
  • There is a narrow band of scapula cartilage along the dorsal border
  • Both dogs and cats have a supratrochlear foramen on their humerus. Nothing passes through this gap in dogs. In cats, the median nerve and brachial vessels pass through this foramen
  • There are no significant modifications of the radius and ulnar bones
  • There are seven carpal bones - this is due to the fusion of the radial and intermediate carpal bones, thus forming the canine “radial” carpal bone
  • The first metacarpal is significantly reduced - it has only two phalanges (P1 and P3) and is a non-weight bearing structure. It only has one associated sesamoid bone and is known as the “dew claw”
  • The distal phalanx carries the horny claw. The flexor process (palmar) is where the deep digital flexor tendon inserts. The extensor process (dorsal) is where the common digital extensor tendon inserts
  • The ungual process is a cone shaped process covered by the horny claw
  • Sesamoids
    • Proximal - pared articulating with MII dorsal. The axial surface is joined by a thick inter-sesamoidean ligament
    • Distal / navicular - boat-shaped, articulated with P2 and P3. Provides a bearing surface for the deep digital flexor tendon, which places it under significant compressive stress

The following videos describe the skeletal system of the canine front limb in detail. The second video discusses other animals as well. The front limb is discussed from 49:11 minutes to 59.37 minutes.

Joints of the Canine Front Limb[edit | edit source]

Scapulo-trunk (scapulo-thoracic)[1][edit | edit source]

  • Type
    • Synsarcotic joint with no attachments (i.e. no clavicle)
  • Supporting structures
    • A series of muscles that sling the trunk from the scapula. This allows for shock absorption and increases range of motion
  • Joint motion and range
    • Cranial glide (NB: caudal, dorsal and ventral glide are described, but not quantified)
    • Winging, tipping and rotation are not described

Shoulder (glenohumeral)[1][edit | edit source]

  • Type
    • Ball and socket joint
    • Consists of glenoid cavity of the scapula and the head of the humerus
    • The glenoid fossa on the scapula is deepened by the glenoid labrum
  • NB: shoulder flexion (and extension) is not the same as limb flexion (and extension). Limb flexion (i.e. protraction) involves shoulder extension
  • The biceps tendon lies over the cranial aspect of the joint and it is held against the humerus by the transverse humeral ligament
  • Glenohumeral ligaments are thickenings of the joint capsule, not true ligaments
  • There are no other ligaments
  • The synovial sheath of the biceps brachii tendon is an extension of the joint capsule

[4]

Shoulder Joint Motion and Ranges[edit | edit source]

Joint Movement Normal ROM for Dogs
Shoulder Extension 30-40 degrees
Flexion 170 degrees
Abduction 40-50 degrees
Adduction 40-50 degrees
Medial rotation 40-50 degrees
Lateral rotation 40-50 degrees

Elbow (humeroradial, humeroulnar, proximal radioulnar)[1][edit | edit source]

  • Type
    • Hinge joint
    • Consists of the humeral condyle, the radius head and semilunar notch of the elbow
  • Ligaments
    • Medial and lateral collateral ligaments. These limit rotation when the elbow is flexed
    • Annular ligament of the radial head

Distal Radial-Ulnar Joint[1][edit | edit source]

  • Part of the antebrachiocarpal joint (shares a joint capsule)

Elbow Joint Range of Motion and Ranges[1][edit | edit source]

Joint Movement Normal ROM for Dogs
Elbow Flexion 25-40 degrees
Extension 170 degrees
Hyper- or over-extension
Radioulnar Pronation 40-50 degrees
Supination 80-90 degrees

Carpal Joint[1][edit | edit source]

  • Hinge joint
  • Radiocarpal (RC) - consists of the trochlear of the radius and carpals
  • Midcarpals (MC) - proximal and distal carpals
  • Carpometacarpals (CMCs) - carpal bones (II-IV) and metacarpals (II to IV)
  • Intercarpals (IC) - carpals of the same row
  • Ligaments of the carpal joint
    • Medial and lateral collateral ligaments
    • Intercarpals
    • Palmar carpal ligament (fibrocartilage)
    • Flexor retinaculum
  • Carpal canal
    • Formed by the accessory carpal bone (laterally), the palmar carpal ligament (cranially) and the flexor retinaculum (palmar)
    • Structures passing through the carpal tunnel include:
      • Tendons and synovial sheaths of the superficial and deep digital flexor tendons
      • Ulnar and median nerves
      • Arteries and veins

Carpus Joint Range of Motion and Ranges[1][edit | edit source]

Joint Movement Normal ROM for Dogs
Carpus Flexion 20-30 degrees
Hyper-extension 10-15 degrees
Radial or medial deviation 15-20 degrees
Ulnar or lateral deviation 15-20 degrees

References[edit | edit source]

  1. 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 Van der Walt A. Managing Disorders of the Canine Front Limb Course. Physioplus, 2021.
  2. Pinoy Vet Anatomist. Skeletal System (Part 4) - Bones of the thoracic limb. Available from: https://www.youtube.com/watch?v=7fZoAHK02n0 [last accessed 28/2/21]
  3. Burnsie's RVT Vids. Skeletal Anatomy Dogs, Cats, Horses, Cows (VETERINARY TECHNICIAN EDUCATION). Available from: https://www.youtube.com/watch?v=6OoFyLHqjLM [last accessed 28/2/21]
  4. Priya Streram. *LEARN* Applied Anatomy of the Canine Shoulder. Available from https://www.youtube.com/watch?v=En4dLdmR4O8 [last accessed 28/2/21]