Muscle Anatomy and Function: Origins, Insertions, and Movements chapter 11

Origin

Stationary attachment point, usually proximally located.

Insertion

Mobile attachment point, usually distally located.

Agonist

The muscle that produces the most force during a particular joint action.

Antagonist

Muscle that opposes the prime mover.

Synergist

Muscle that aids the prime mover.

Fixator

Muscle that prevents a bone from moving.

Biceps brachii

Muscle located in the upper arm.

Ceps

Refers to the number of origins; Biceps has 2 origins or 'heads'.

Sternocleidomastoid

Muscle involved in neck flexion and rotation to the opposite side.

Gluteus Maximus

Muscle named for its size.

Deltoid

Muscle named for its triangular shape.

Flexors

Muscles located on the ventral side, except for knee flexors which are on the posterior.

Extensors

Muscles located on the dorsal side, except for knee extensors which are on the anterior.

Obicularis oculi

Muscle that closes the eyes.

Obicularis oris

Muscle that closes and puckers the mouth.

Zygomaticus Major

Muscle that inserts into the corner of the mouth.

Mentalis

Muscle responsible for pulling down the lower lip.

Buccinator

Muscle that holds food between cheek and teeth and compresses cheeks.

Masseter

Muscle involved in closing the mouth (chewing) with no skin insertion.

Scalenes

Deep neck muscles that assist in breathing and lift the rib cage.

Trapezius Muscle

Muscle located in the upper back.

Rotator Cuff (SITS muscles)

Group of muscles including Supraspinatus, Infraspinatus, Teres Minor, and Subscapularis that stabilize the shoulder.

Supraspinatus

Shoulder abduction

Infraspinatus

Lateral rotation of shoulder

Teres minor

Lateral rotation and adduction

Subscapularis

Medial rotation of the shoulder

Rhomboid

Scapula stabilization

Serratus anterior

Pull scapula down and forward

Teres major & Latissimus dorsi

Synergists for medial rotation

Teres minor & Infraspinatus

Synergists for lateral rotation

Triceps brachii

Function not specified

Aponeurosis

Flat tendon: Linea Alba

External oblique

Compress abdomen

Internal oblique

Compress abdomen

Transverse abdominis

Compress abdomen

Rectus abdominis

Trunk flexion

Diaphragm

Breathing muscle

Iliopsoas

Prime mover for hip flexion

Sartorius

Spans 2 joints: Anterior, Superior Iliac Spine → Medial tibia

Rectus femoris of quadriceps femoris

Spans 2 joints: Anterior, inferior iliac spine → Tibial tuberosity

Hamstring

Dorsal side: Span 2 joints, Action: Hip extension & knee flexion

Gastrocnemius

Flexes knee and plantar flexes ankle

Soleus

Plantar flexes ankle (only)

Tibialis anterior

Dorsiflexes ankle