muscles will kleinelp associate professor, biology ©2007
TRANSCRIPT
MUSCLESWill Kleinelp
Associate Professor, Biology©2007
MUSCLES OF THE HEAD AND NECK
Digastric
ORIGINAnterior belly: digastric fossa on posterior surface of symphysis menti.
posterior belly: base of medial aspect of mastoid process
INSERTIONFibrous loop to lesser cornu of hyoid bone
ACTIONElevates hyoid bone. Aids swallowing and depresses mandible
Mylohyoid
ORIGINMylohyoid line on internal aspect of mandible
INSERTIONAnterior three quarters : midline raphe. posterior
quarter: superior border of body of hyoid bone
ACTIONElevates hyoid bone, supports and raises floor of
mouth. Aids in mastication and swallowing
Masseter
ORIGINAnterior two thirds of zygomatic arch and zygomatic process of maxilla
INSERTIONLateral surface of angle and lower ramus of mandible
ACTIONElevates mandible (enables forced closure of mouth)
Sternocleidomastoid
ORIGINAnterior and superior manubrium and superior medial
third of clavicle
INSERTIONLateral aspect of mastoid process and anterior half of
superior nuchal line
ACTIONFlexes and laterally rotates cervical spine. Protracts
head when acting together . Extends neck when neck already partially extended
ORIGINTemporal fossa between inferior temporal line
and infratemporal crest
INSERTIONMedial and anterior aspect of coronoid process
of mandible
ACTIONElevates mandible and posterior fibers retract
Temporalis
Occipitalis
Orbicularis oris
ORIGINNear midline on anterior surface of maxilla and
mandible and modiolus at angle of mouth
INSERTIONMucous membrane of margin of lips and raphe
with buccinator at modiolus
ACTIONNarrows orifice of mouth, purses lips and
puckers lip edges
Orbicularis oculi
ORIGINMedial orbital margin and lacrimal sac (orbital,
palpebral and lacrimal parts) INSERTIONLateral palpebral raphe
ACTIONCloses eyelids, aids passage and drainage of
tea
Buccinator
ORIGINExternal alveolar margins of maxilla and mandible by
molar teeth, to maxillary tubercle and pterygoid hamulus and posterior mylohyoid line respectively, then via pterygomandibular raphe between bones
INSERTIONDecussates at modiolus of mouth and interdigitates with
opposite side
ACTIONAids mastication, tenses cheeks in blowing and whistling,
aids closure of mouth
Scalenes (anterior)
ORIGINAnterior tubercles of transverse processes
of C3-6 INSERTIONScalene tubercle on superior aspect of 1st
rib
ACTIONAccessory to inspiration. lateral flexion of
neck when 1st rib fixed
Splenius
ORIGINLower ligament nuchae, spinous processes and
supraspinous ligaments T1-3
INSERTIONLateral occiput between superior and inferior nuchal lines
ACTIONExtends and rotates cervical spine
Zygomaticus Major
ORIGINAnterior surface of zygomatic bone
INSERTIONModiolus at angle of mouth
ACTIONElevates and draws angle of mouth
laterally
Zygomaticus Minor
ORIGINLateral infra-orbital margin
INSERTIONSkin and muscle of upper lip
ACTIONElevates and everts upper lip
MUSCLES OF THE CHEST ABDOMEN & SPINE
Pectoralis Major
ORIGINClavicular head-medial half clavicle.
Sternocostal head-lateral manubrium and sternum, six upper costal cartilages and external oblique aponeurosis
INSERTIONLateral lip of bicipital groove of humerus and
anterior lip of deltoid tuberosity
ACTIONClavicular head:flexes and adducts arm.
Sternal head: adducts and medially rotates arm . Accessory for inspiration
Pectoralis Minor
ORIGIN3, 4, 5 ribs
INSERTIONMedial and upper surface of
coracoid process of scapula
ACTIONElevates ribs if scapula fixed,
protracts scapula (assists serratus anterior)
External Oblique
ORIGINAnterior angles of lower eight ribs
INSERTIONOuter anterior half of iliac crest, inguinal lig,
public tubercle and crest, and aponeurosis of anterior rectus sheath
ACTIONSupports abdominal wall, assists forced
expiration, aids raising intraabdominal pressure and, with muscles of opposite side, abducts and rotates trunk
Internal Oblique
ORIGINOrbital surface of maxilla behind
orbital margin
INSERTIONPost/inferior quadrant of sclera
behind equator of eyeball
ACTIONElevates eye in adduction.
Laterally rotates eye in abduction
Transversus abdominis
ORIGINCostal margin, lumbar fascia, anterior two thirds
of iliac crest and lateral half of inguinal ligament
INSERTIONAponeurosis of posterior and anterior rectus
sheath and conjoint tendon to pubic crest and pectineal line
ACTIONSupports abdominal wall, aids forced expiration
and raising intra-abdominal pressure. Conjoint tendon supports posterior wall of inguinal canal
Rectus abdominis
ORIGINPubic crest and pubic symphysis
INSERTION5, 6, 7 costal cartilages, medial
inferiorcostal margin and posterior aspect of xiphoid
ACTIONFlexes trunk, aids forced expiration and
raise intra-abdominal pressure
External Intercostals
ORIGINInferior border of ribs as far back as
posterior angles
INSERTIONSuperior border of ribs below, passing
obliquely downwards and backwards
ACTIONFix intercostal spaces during respiration.
Aids forced inspiration by elevating ribs
Internal Intercostals
ORIGINInferior border of ribs as far back as
posterior angles
INSERTIONSuperior border of ribs below , passing
obliquely downwards and backwards
ACTIONFix intercostal spaces during espiration.
Aids forced inspiration by elevating ribs
Diaphragm
ORIGINVertebral:crura from bodies of L1, 2 (left), L1-3
(right). Costal: medial and lateral arcuate ligs, inner aspect of lower six ribs . Sternal: two slips from posterior aspect of xiphoid
INSERTIONCentral tendon
ACTIONInspiration and assists in raising intra-abdominal
pressure
Erector SpinaeSacrospinalis
ORIGINTransverse processes
INSERTIONTransverse processes several levels above
ACTIONExtends spine
Muscles for Next Week OIA
A. Head and Neck
Epicranial Muscles
2.Frontalis
1. Occipitalis
2. Orbicularis oculi
3. Zygomaticus
4. Buccinator (deep)
5. Temporalis
6. Masseter
7. Digastric (both bellies)
8. Mylohyoid
9. Orbicularis oris
10. Platysma
11. Sternocleidomastoid
12. Sternohyoid
15. Omohyoid (2 bellies)
16. Scalanes group
a) Anterior
b) Posterior
c) Middle
17. Splenius (deep)
18. Longissimus thoracis (erector spinae)
B. Chest and Abdomen
1. Pectoralis major
2. Pectoralis minor
(deep)
3. Serratus anterior
4. External
intercostals (deep)
5. Internal intercostals
(deep)
6. Diaphragm (deep)
7. External oblique
8. Internal oblique
(deep)
9. Transversus abdominis
(deep)
10. Rectus abdominis