These are involved  in changing  facial  expression,  movement  of lower  jaw during eating and  speaking.

MUSCLES  OF THE FACE

Occipito- frontalis muscle

This consists of a posterior part which  covers  the occipital bone (occipitalis). It has an  anterior  part  over the  frontal  bone  (frontalis). It has an extensive  tendon  or aponuerosis  that stretches  over the  dome  of the skull and joins  the two  muscular  parts.

Function

It raises the eye blows.

NB: Write short notes on the following muscles: masseter, buccinators, orbicularis oris, orbicularis oculi, lavatory palpabrae,

MUSCLES OF THE NECK

Sternocleido mastoid muscle

• This rises from  the manuarium  of the sternum  and  clavicle and  extends  upwards  to the  mastoid  process of  the temporal bone.
• It insists  in turning  the head side to side.
• When  the muscle  on one side contracts  it draws the head  towards  the shoulder.
• When both contract at the same  time they  flex the cervical  vertebra  or draw  the  stemum  and clavicle upwards  when a head is maintained  in a fixed  position most especially  in forced  respiration.

Trapezius

• This covers the  shoulders and part  of the neck .
• The upper attachment  is to  the occipital protuberance   and the  media attachment  is transverse  process of  thoracic  and cervical  vertebra.
• The lateral  attachment  is to the  clavicle and  to the  spinous  and to the  spinous  and acromion  process of  the  scapular function.
• It pulls  the head  back words, and  squares  the shoulder  and control the movement  of the scapula when the shoulder  joints is in use.

MUSCLES  OF THE SHOULDER & UPPER LIMB

These  muscles  stabilize  the association  between the  appendicular  and axial  skeleton  at the pectral  girdle. It stabilizes  and allows  movement  of the upper arm.

Deltoid muscle

• Muscle  fibres  orginate  from the clavicle,  acromion  process and  spine  of the scapula  and radiates  over the  shoulder  joint.
• It is  inserted into  the Deltiod tuberosity  of the humerous.
• It forms  the fleshy  and rounded  contour of the shoulder.

Function

Helps in the movement of  the arm ie  flexion, abduction, and rotation  of the shoulder  joint.

Pectaralis  major

• Lies in the anterior from  the middle  side of the  clavicle  and sternum  and it is  inserted into the  intertubercular groove  of the humenous.
• It draws  the arm  forward and towards  the body ie flexes  and adducts.

Caraco  branchialis

It lies  in the upper medial  aspect  of the arm. It rises  from the coracoid process  of the scapula  stretches  across  infront  of the  shoulder  joint. It is inserted  into the mid of the humerous.

Function

Flexes  the shoulder  joint.

Biceps

• Lies  on the anterior  aspects  of the upper arm.
• Its proximal  end is  divided into  two parts  (heads) each of  which has its own  tendon.
• The short  head raises  from the  coracoids process of  the scapula  and passes  infront  of the shoulder  joint  to the arm.
• The long head  originate  from the rim of the glenoid cavity  and its tendon  passes  through the  joint cavity and the bicipital  groove  of the humerous  of the arm. 
• Its  retained  in the  Bicipital  groove  by a transverse  humeral  ligament  that stretches  across the  groove. The distal  tendon  cross the  elbow  joint  and is  inserted  into the  radial  tuberosity.
• It helps  to stabilize  as flex  the shoulder  joint  and at the  elbow  joint  it assist  with flexion  and supination.

Bronchialis

• Lies  on the  anterior  aspect of  the upper arm deep  to the  biceps.
• Originates from the shaft  of the humenous,  extends  across  the elbow  joint and is inserted into the Ulna just  distal to  the joint  capsule. It is the  main flexor of  the elbow  joint.

Triceps

• This lies on the posterior  aspect  of the humerous.
• It arises from  three heads. One on the  scapula and two from  the posterior  surface  of the humerous.
• The insertion  is by a common tendon  to the acranon  process  of  the Ulna.
• It helps  to stabilize  the shoulder  joint,  assists in adduction  of the arm  and extends  the elbow joint.

Branchioradialis

• This spans  the elbow  joint,  originates  on the distal end  of the humerous  and inserts  on the lateral  epicodyle  of the radius. contraction  flexes  the elbow  joint.

Pronator quadratus

• This square  shaped  muscle  is the main muscle  causing  pronation  of the hand  and has attachments  on the lower  sections  of both the  radius  and Ulna.

Pronator teres

• It lies  obliquely  across the  upper king  of the front  of the fore arm.
• It arises  from the  medial  epicondyle  of the humerus  and the coronoid  process  of the Ulna and  passes  obliquely  across the  fore arm  to be inserted  into the  lateral  surface  of the shaft  of the  radius. It rotates  the radioulnar  joints,  changing  the hand from  the  anatomical  to  the writing  position  ie pronation.

 Supinator

• Lies obliquely  across the posterior and lateral aspects  of the fore arm
• Its  fibres  arise from  the lateral  epicandyle of the humerus  and the upper  part of the  Ulna  and are inserted  into the lateral  surface  of the upper  third of the  radius.
• It rotates  the radioulnar  joints  often with  help  from  the biceps,  changing  the  hand from  the writing to  the anatomical  position  ie  supination.
• It lies  deep  to the muscles.

Flexor  carpi radialis

• It lies on the  anterior surface  of the forearm.
• It originates  from the medial epicondyle  of the humeos and is  inserted into  the second and  third metacarpal  bones.
• It flexes  the wrist  joint, and when acting  with  the extensor  carpi radials , abducts  the joint.

Flexer  carpi  ulnaris

• It lies on the medial  aspect  of the forearm.
• It originates  from the  medial  epicondlye  of the  humerous  and the upper parts  of the Ulna  and is inserted  into the  pisform, the hamate  and the fifth  metacarpal  bones.
• It flexes the wrist and when  acting  with the  extensor  carpi  ulnaris, adducts  the joint.

Extensor  carpi  radialis longus  and brevis

• These lie  on the  posterior aspect of  the fore arm.
• The fibres originate from the lateral epicondyle  of the  humerus and  are inserted  by along tendon  into the second and third  metacarpal  bones.  They extend  and abduct  the wrist.

Extensor carpi ulnaris

• It lies on the posterior surface  of the fore arm.
• It originates  from the  lateral  epicandyle  of the humerus  and is inserted into the fifth  metacarpal  bone. It extends  and adducts  the wrist.

Palmaris longus

• This muscle  resists  shearing  forces that  might pull the skin  and fascia of the palm  away from the underlying  structures,  and flexes  the wrist.
• Its origin  is on the medial epicandlye  of the humerus,  and it inserts  on tendons  of the palm  of the hand.

Extensor  digitorum

• This muscles originates  on the lateral epicondyle  of the  humerus  and spans both the  elbow and wrist  joints,  in the wrist,  it divides  into four  tendons, one for each finger.
•  Action of  this muscle can extend  any of the  joints  across  which it passes ie the  elbow,  wrist  or finger joints.

Diagram