Epicranius
- divided into 2 parts - overlies top of skull
Fontalis
over forehead - consists of 2 bellies
-draws scalp forward - wrinkles forehead - raises eyebrows
-insertion: superficial fascia of eyebrow
-origin: Galea aponeurotica (epicranial aponeurosis)
Occipitalis
over occipital bone
-draws scalp backward (wiggles your ears)
-insertion: Galea aponeurotica (epicranial aponeurosis)
-origin: Occipital bone
Orbicubris oris
- sphincter muscle surrounding mouth opening
- closes and compresses lips, protrudes lips, shapes for speech
origin and insertion - muscles arranged in circular pattern with variety of origins and insertions.
c
Zygomaticus major
- runs obliquely across the front of the face from upper corner of mouth
-draws the angle of mouth upward and outward - assists in parting lips
-origin: zygomatic bone
-insertion: fascia around mouth's angle (lateral corner)
Levator labii superioris
- runs superior to lip, parallel to nose
-assists in raising and parting lips
-origin: near orbit, on maxillae
-insertion: fascia around upper lip
Depressor labii inferioris
- depresses lower lip
-origin: mandible
-insertion: skin of lower lip
*lateral to mentalis
Mentalis
(chin) - protrudes lower lip - elevates skin over chin - pouting muscle
-origin: mandible near lower lip
-insertion: fascia of chin
*medial to Depressor labii inferioris
Buccinator
(cheek) - makes up most of mass of cheek
-compresses cheeks (blowing and sucking)
-origin: alveolar processes of maxilla and mandible and from pterygomandibular ligament (raphe)
-insertion: fascia of lower lateral face
Platysma
- (flat, broad) - very superficial muscle covering lower face and neck
-draws skin around mouth laterally and inferiorly
-origin: fascia over deltoid and pectoralis muscles
-insertion: fascia of lower lateral face
Risorius
- (laughter) - runs laterally from corners of mouth
-origin: fascia over parotid gland
-insertion: fascia at corners of mouth
Orbicularis Oculi
- circular muscle around orbit
-origin and insertion: circular locations around orbit (many)
*functions sphincter like to close the eye
Levator palpebrae superioris
- functions to elevate upper eyelid.
-actually a muscle of the orbit - courses over eyeball to eyelid
-origin: lesser wing of sphenoid (orbital root)
-insertion: superior tarsal plate of upper lid.
Corrugator Supercilii
- small muscle deep to orbicular is oculi
-responsible for angry look
-origin: medial part of superciliary arch
-insertion: fascia and skin of eyebrow
Muscles of Mastication
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Masseter
- elevates the mandible - most powerful
-origin: zygomatic arch
-insertion: angle and ramus of mandible
Temporalis
- elevates and retracts mandible
-origin: fan shaped over the temporal bone
-insertion: coronoid process and anterior border of ramus of mandible
Medial pterygoid
- elevates and protrudes mandible - also functions in moving the mandible from side to side in chewing.
-origin: medial side of lateral pterygoid plate and from maxilla
-insertion: medial surface of angle of mandible
Lateral pterygoid
- pulls mandible forward to open mouth and also assists in side to side movement.
-origin: greater wing of sphenoid and lateral side of later pterygoid plate
-insertion: condyle of mandible and articular disk of T.M.J.
Mylohyoid
- flat muscle making up lower floor of mandible - elevates floor of mouth
-origin: inferior portion of mandible
-insertion: a midline raphe and the hyoid bone
Stylohoid
- elevates and retracts the tongue
-origin: styloid process of temporal bone
-insertion: body of hyoid bone
Genioglossus and Geniohyoid
- Protracts the tongue and depresses the tongue
-origin: anterior inferior portion of the mandible (superior genial tubercle)
-insertion: fans out into the mass of the tongue - some to tip - some to dorsum of tongue - some posterior. Geniohyoid inserts on
Styloglossus
- elevates and retracts the tongue
-origin: Styloid process
-insertion: fibers merge into the side and under surface of the tongue
Hyoglossus
- Depresses the tongue
-origin: Body and cornu of hyoid bone
-insertion: fibers merge with fibers of other muscles in the side of the tongue
Muscles That Move The Head
3
Sternocleidomastoid
- flexes the neck or rotates head from side to side
-origin: sternum and clavicle
-insertion: mastoid process
Semispinalis Capitis
- extends the head at the neck or rotates from side to side
-origin: seventh cervical, and first 6 thoracic vertebrae
-insertion: occipital bone
Splenius Capitis
- extension or rotation of head
-origin: Ligamentum nuchae and seventh cervical and first 4 thoracic vertebrae
-insertion: occipital bone
Muscles of Anterior Abdominal Wall
4
Rectus Abdominus
- strap-like muscle on medial abdomen.
-origin: pubic symphysis and pubic crest
-insertion: cartilage of sixth and seventh ribs and xyphoid.
-anterior surface is crossed by linea alba vertically at midline and by several horizontal "tendinous intersection
External Oblique
- courses obliquely downward across abdomen
-most outer layer of muscle
-compresses abdomen or may assist in lateral bending
-note: aponeurosis forming rectus sheath crosses over rectus muscle
-origin: lower 8 ribs
-insertion: midline aponeurosis
Internal Oblique
courses oblique in upward direction across abdomen
-function = same as external
-aponeurosis forming rectus sheath divides and goes both over and under rectus abdominus muscle
-origin: Lumbar fascia; iliac crest, and partially from inguinal ligament
-inse
Transversus abdominus
- lies deep to internal oblique
-fibers run horizontally and forward
-aponeurosis forming rectus sheath passes posterior to rectus abdominus
-origin: Lumbar fascia, iliac crest, inner part of last 6 ribs and cartilage
-insertion: xyphoid process, rectus s
Muscles of Pelvic Floor
4
Levator ani
divided into 2 parts - funnel shaped
Pubococcygeus
part of Levorator ani, Pubis-coccyx
Iliococcygeus
part of Levorator ani, Ilium-coccyx
Coccygeus
- Ischial Tuberosity - Coccyx (sometimes called Ischiococcygeus)
Puborectalis
sometimes authors incude
Pelvic Diaphram
are these 3 muscles form it.
This forms an efficient muscular sling that supports pelvic viscera. The Levator ani muscles also have an important sphincter action on the anorectal junction - in the female they serve as a sphincter for vagina - also help to
Perineum
3 muscles
Urogenital diaphragm
- musculofacial diaphragm situated in anterior part of perineum. Formed by the following muscles which are enclosed with fascia above and below
1. Sphincter Urethrae
2.Deep Perineal muscle
*these muscles may assist in helping prevent flow of materials out of urethra - also assist in ejaculating remaining fluid (semen or urine)
Muscles associated with genitalia
1. Bulbospongiosis (Bulbocavernosus)
2. Ischiocavernosus
Sphincter ani externus
- keeps anal orifice closed
-origin and insertion unimportant
Muscles of Shoulder
14
Pectoralis Major
- some function in flexing arm - but mostly for adduction and medial rotation
-origin: clavicle and sternum and partly from some costal cartilage
-insertion: greater tubercle of humerus
Pectoralis Minor
- deep to Pectoralis Major
-Primary action is to fix the scapula - also accessory muscle for respiration
-origin: medial ends of ribs 2-4
-insertion: coracoid process of scapula
Subclavius
depresses the clavicle and steadies it during movements of shoulder girdle - relatively unimportant muscle
- origin: first rib
- insertion: clavicle
Serratus Anterior
functions to draw the scapula forward and lateral on thoracic wall - also, due to greater pull on inferior angle causes lateral rotation
- origin: anteriolateral surface of upper 8-9 ribs
- insertion: the medial anterior border of scapula
Deltoid
- triangularly shaped muscle that abducts the arm primarily
- origin: clavicle, acromion, and spine of scapula
- insertion: deltoid tuberosity of humerus
*actually actions of deltoid are many besides abduction of arm, either flex and medially rotate or ex
Trapezius
an elevator of lateral angle of the scapula - enabling one to touch head - also retracts scapula and can extend the head.
- origin: occipital bone and ligamentum nuchae and spinous processes of thoracic vertebrae.
- insertion: spine and acromion of scapul
Levator Scapulae
elevator of the superior angle of scapula. In doing so tends to retract and elevate scapula.
-origin: first 3-4 cervical vertebrae
-insertion: superior angle of scapula
Rhomboideus Major and Minor
these two muscles are frequently fused to form 1 muscle. Chief actions - retraction and elevation of the scapula (adduction).
-origin: lower ligamentum nuchae and spinous processes of upper 5-6 thoracic vertebrae.
-insertion: medial border of scapula
Latissimus Dorsi
- adductor, medial rotator, and extensor of arm
-origin: very extensive, from spinous processes of lower thoracic, lumbar, and sacral vertebrae. Also from posterior iliac crest.
-insertion: wraps around medial side of humerus and inserts on intertubercula
Supraspinatus
- abductor of the arm (some slight abduction is associated with almost all movement of arm)
-origin: bony walls of the supraspinatus fossa of scapula. Passes laterally inferior to acromion to;
-insertion: upper greater tubercle of humerus
Infraspinatus
primary function is lateral rotation of humerus
-origin: infraspinatus fossa of the scapula - courses around outside of humerus to:
-insertion: greater tubercle
Teres Minor
primary action is lateral rotator of humerus (like infraspinatus)
-origin: lateral (axillary) border of scapula
-insertion: greater tubercle of humerus
Teres Major
acts as an extensor, adductor, and medial rotator of humerus
-origin: inferior angle of scapula - fibers course medial to humerus to
-insertion: with Latissimus dorsi in intertubercular groove
Subscapularis
- medial rotator of arm
-origin: subscapular fossa of scapula
-insertion: lesser tuberosity of humerus
Rotator Cuff
four scapular muscles which form a musculotendinous cuff around the shoulder joint. The muscles are the supraspinatus, infraspinatus, teres minor, and subscapularis (SITS). These are all rotators of the shoulder except the supraspinatus, however this musc
Muscles of Upper Extremity
10
Biceps Brachii
- arises from 2 heads (origin)
-short head - coracoid process of scapula
-long head - supraglenoid tubercle of the scapula
*these two bellies fuse for common insertion at radial tuberosity
*since muscle crosses 2 joints - can have some function at either
Brachialis
- flexion of forearm is sole function.
-origin: from lower 1/2 of humerus on anterior side
-insertion: coronoid process of ulna
Coracobrachialis
- adduction and flexion of arm
-origin: from coracoid process of scapula to:
-insertion: medial border of the humerus about "mid-arm
Triceps Brachii
- arises from 3 heads
1. lateral head - posterior surface of upper humerus
2. long head - infraglenoid tubercle of scapula
3. medial head - deep to other two heads - from posterior surface of humerus inferior and medial to origin of lateral head.
*primary
Brachioradialis
- flexor of the forearm
-origin: supracondylar ridge of the humerus (lateral side)
-insertion: just superior to the styloid process of the radius
Pronator Teres
pronates the forearm
-origin: Medial epicondyle of the humerus and coronoid process of ulna.
-insertion: Shaft of the radius (middle of lateral side)
Supinator
- supinates the forearm (note: Biceps is chief supinator)
-origin: lateral epicondyle of the humerus and posterior portion of ulna
-insertion: shaft of the radius
Flexors of wrist and digits
ventral forearm
Extensors of the wrist and digits
dorsal forearm
Dorsal and Palmar interossei
muscles - between metacarpals of hand - responsible for adduction and abduction of digits
muscles used for breathing
3
Diaphragm
Diaphragm - form roof of abdominal cavity and floor of the thoracic cavity. Works like a bellows to create negative pressure in lungs and thus inspiration, then positive pressure for expiration.
-origin: lumbar vertebrae, lower six ribs and cartilages and
External Intercostals
- run obliquely downward from lateral to medial. Draw ribs together thus elevating them and assisting to create negative pressure in thorax for inspiration.
-origin and insertion: rib to rib
Internal Intercostals
- same as external except run obliquely downward from medial to lateral - lay directly beneath external intercostals (deep to them) - pull ribs together in forced expiration.
Muscles of the lower extremity
17
Gluteus Maximus
- extends and laterally rotates the thigh
-mostly used during action requiring considerable muscular effort - used when raising from sitting or stooping position.
-origin: iliac crest, sacrum, coccyx, (and sacrotuberus ligament)
-insertion: lateral side o
Gluteus Medius and Minimus
-origin: both from Ilium
-insertion: superior lateral surface of greater trochanter
*for the most part - abduction of hip
also both medial rotators of hip
*most important function is to stabilize the pelvis during walking as opposite foot leaves the groun
Tensor fascia lata
origin: iliac crest
-insertion: into iliotibial tract which inserts near lateral condyle of tibia.
-enclosed within fascia lata - a flexor and abductor of the hip.
- extends the knee
Iliopsoas
- composed of Psoas and Iliacus muscles
Psoas - arises from lumbar vertebral bodies and transverse processes
Iliacus
- fan-shaped - comes from upper part of iliac fossa
-insertion: fibers fuse and insert via common tendon on the lesser trochanter of femur.
-action: flexes the thigh (e.g. lifting leg or raising from lying to sitting position)
Adductors
(longus, brevis, magnus)
-origin: pubis (magnus also from ischium)
-insertion: linea aspera of femur
* adductors of thigh - also flexors (magnus can extend)
Quadriceps femoris
- powerful group of muscles for extending the knee (rectus femoris also helps flex the hip)
Rectus Femoris - origin: anterior inferior iliac spine
Vastus Lateralis
Vastus Medialis - origin: femur itself (upper portion)
-Vastus Intermedius
-insertion: all
Sartorius
(tailor's muscle) - runs obliquely across thigh from lateral to medial
-origin: anterior superior iliac spine
-insertion: medial surface of shaft of tibia
-acts at two joints
a.flexes, abducts, and laterally rotates thigh at hip
b.flexes and medially rota
Gracilis
on medial side of thigh - adductor of thigh and flexor of leg
Hamstrings
a collective grouping (for naming) of 3 large muscles in posterior compartment of thigh.
1. Biceps femoris
- origin: from two heads
a. long head - ischial tuberosity
b. short head - femur
-insertion: lateral condyle of tibia and head of fibula
2. Semitendinosis
-origin: ischial tuberosity
-insertion: medial shaft of tibia
3. Semimembranosis
-origin: ischial tuberosity
-insertion: medial condyle of tibia
*collectively the hamstrings all function to flex the leg and extend the thigh
Gastrocnemius
- origin: lateral head - lateral condyle of femur medial head - just above medial condyle of femur
-insertion: tendocalcaneus (Achilles tendon)
*plantar flexor of foot - also assists in flexion of the knee.
Soleus
-origin: posterior surface of tibia and head of fibula
- insertion: tendocalcaneus
*plantar flexor of foot
-together with plantaris and Gastrocnemius - it provides main forward propulsive force in walking and running by using foot as a lever
Tibialis Posterior, Flexor Digitorum Longus, and Flexor Hallucis Longus
- Three muscles of the deep portion of the posterior compartment
- Tendons wrap around the medial malleolus and insert on the bottom of the foot
Fibularis (Peroneus) Longus and Brevis
- both found in lateral compartment of the leg and are responsible for plantar flexion and eversion of the foot.
-origin: both arise from fibula with tendon wrapping under lateral malleus
-insertion: inferior aspect of foot
-longus: medial cuneiform and f
Tibialis Anterior
-origin: upper 1/2 of lateral aspect of tibia and interossous membrane
-insertion: tendon passes through extensor retinaculum and attaches to medial cuneiform
Extensor Digitorum Longus
a muscle in the anterior compartment of the leg that dorsiflexes the foot and extends the toes (passes through extensor retinaculum)
Extensor Hallucis Longus
is a muscle in the anterior compartment of the leg that extends the hallux (big toe)
Deep Muscles of the Back
2
For deep muscles of the back - muscles that move the vertebral column - there are really only 2 important ones to know.
Quadratus Lumborum
- flexes vertebral column laterally
-origin: iliac crest
-insertion: upper lumbar vertebrae and lowest rib
Sacrospinalis or Erector Spinae
-extends the vertebral column and maintains it in an erect position.
-extends from the iliac crest and sacrum to the neck and base of the skull - Divided into 3 major muscle groups.
1. Iliocostalis
- most lateral of 3 groups
-made up of iliocostalis lumborum, iliocostalis thoracicus, and iliocostalis cervicus
2. Spinalis (Spinalis thoracicus)
most medial of 3 muscle groups
3. Longissimus
-intermediate between other 2 groups
-can be further divided into Longissimus thoracicus, Longissimus cervicus, and Longissimus capitis.