In: Anatomy and Physiology
Describe the qualities of the muscle fiber arrangement and tendon attachments of the triceps brachii. Also, discuss synergist(s) and antagonist(s) muscles and their attachment sites. Describe when synergists and antagonists contract compared to your assigned muscle
Triceps brachi = Tri (three) and ceps ( heads)
Long head: infraglenoid tubercle of
scapula
Lateral head: above the radial groove
Medial head: below the radial groove.
Insertion --Olecranon process of ulna
Nerve-Radial nerve and Axillary nerve
Actions -Extends forearm at elbow joint, long head extension, adduction arm, Extension at shoulder joint .
Antagonist--Biceps brachii muscle
Biceps brachi (fusiform muscles )
Origin -
Short head: coracoid process of the scapula.
Long head: supraglenoid tubercle.
Insertion -
Radial tubersoity and Bicipital appponeurosis into deep fascia on
medial aspect of forearm
Nerve supply
Musculocutaneous nerve (C3,4,5)
Actions
Flexion at elbow joint
Flexion and abduction at shoulder joint
Supination of radioulnar joint
A synergist muscle are those muscles which stabilizes a joint around which movement is occurring and it helps to create movement.
Agonist muscles are muscles which are activated and contraction occur for prime movement at joint (Prime movers ).
A antagonist muscle is the muscle that opposes the agonist.
The theory of reciprocal inhibition states that When the central nervous system sends a message to the agonist to contract, the tension in the antagonist is inhibited by impulses from motor neurons, and thus must simultaneously relax.In thus way synergist and antagonist muscles act.
Eg During flexion at elbow joint synergist muscles are biceps brachi and brachialis which contract to produce movement and antagonist triceps relax for smooth movement to occur
Extesion at elbow joint -- synergist triceps and antagonist is biceps brachi.