Advanced Anatomy: Superficial Muscles

So once you have a grasp of parts and skeletal structure, the next piece is the superficial muscles. Unfortunately this is pretty well brute memorization; we'll have something more fun next week! In the interim, it's much easier to remember if you think about what the muscles do as much as what they are called.

Some basic terminology as far as what muscles do:

Adduct - move towards the midline
Abduct - move away from the midline
Muscles are divided into three groups:
Cardiac - in the heart
Smooth - in autonomic systems (ie the digestive tract)
Skeletal - used to move bones (usually in pairs)
For today's Theory Thursday we'll be focusing on the superficial skeletal muscles. This diagram comes from the Horse Anatomy Colouring Atlas.



1 - Superior labial levator
2 - Canine
3 - Nasolabial levator
4 - Masseter: large muscles of the jowl, used in chewing
5 - Sternomandibular: incline head and neck (alone), flex head (together); hence why it is easier to keep your horse round when he's flexed.
6 - Cervical cutaneous
7 - Brachiocephalic: long muscle from the poll to the upper arm. It pulls the limb forward, extends the shoulder, and bends the head and neck
8 - Splenius: muscles at the top of neck running to the shoulder blade. Responsible for lifting the head, pulling the scapula forward and up, bend neck
9 - Cervical ventral serrated
10 - Thoracic ventral serrated
11, 12 - Cervical and Thoracic Trapezius: muscles at the top of the neck and behind the withers. Pulls the should forward (cervical), back (thoracic) and up (together). Carries the saddle.
13 - Subclavian
14 - Deltoid: flexes shoulder, abducts limb.
15 - Latissimus dorsi: muscle running along back and down the barrel to the back of the shoulder blade. Supports the saddle, pulls humerus up and back. Flexes shoulder.
16 - Descending pectoral: advance limb
17 - Brachial triceps: large muscle from elbow to bottom of should blade. Extends elbow and foreleg.
18 - Ascending pectoral - adduct and retract limb
19 - Carpal and digital extensor - muscles of forearm that extend leg; flex elbow

So if the extensor muscles extend the list the flexor muscles . . . ? - comeon, wild guess here.... That's right, flexor muscles flex the leg.
Extensor muscles on the front of the leg to pull it forwards, flexor muscles on the back to bring it back.

20 - External obdominal oblique - support and compress abdominal content
21 - Tensor of the fascia lata
22 - Superficial gluteal - flexes hip
23 - Femoral biceps - extend hip, stifle, hock
24 - Semitendinous - extend hip and hock
25 - Digital extensor
(which does.... what? Extend the digit perhaps?)