anat 316 pt 2 bs

Mastication

• Mastication: process by which food is crushed and ground by the teeth

• Associated with the temporomandibular joint (TMJ)

Temporomandibular Joint (TMJ)

• Elevation, depression, protraction, retraction, side to side movement

Muscles of Mastication

Temporalis

• O: Temporal Fossa (temporal bone and surrounding areas)

• I: Coronoid Process of Mandible

• A: Elevate + Retract Mandible

Masseter

• O: Zygomatic Arch

• I: Ramus + Angle of Mandible

• A: Elevate Mandible (with force)

• Powerhouse of mastication

Lateral Pterygoid

• O: Sphenoid Bone

• I: Condyle of Mandible

• A: Depression, Protraction, Side to side movement of Mandible

Medial Pterygoid

• O: Sphenoid Bone

• I: Angle of Mandible

• A: Elevate Mandible

Muscles of Mastication: Innervation

• Primary muscles of mastication innervated by the mandibular nerve (CNV3)

• Mandibular Nerve = 3rd branch (mandibular branch) of CN V (trigeminal)

Muscles of Mastication: Blood Supply

• Primary muscles of mastication supplied by branches of the maxillary artery

Buccinator

• Important muscle in facial expression

• Accessory muscle of mastication – keeps food in oral cavity

• Innervated by: CNVII

Anterior Neck Muscles

Responsible for moving the head and neck

Platysma

• O: Clavicle

• I: Mandible

• A: Depresses mandible (draws corners of the mouth inferiorly

• Innervation: CNVII

Sternocleidomastoid (SCM)

• O: Sternum and Clavicle

• I: Mastoid process

• A:

  • Unilateral contraction – lateral flexion of neck, head rotation to opposite side

  • Bilateral contraction – head flexion (nod)

• Innervation: CNXI

Scalene Muscles

• Group of 3 muscles, deep within the anterolateral neck: Scalenus Anterior, Scalenus Medius, Scalenus Posterior

• O: Transverse processes of cervical vertebrae

• I: Superior Ribs (Rib 1, 2)

• A:

  • Unilateral contraction – lateral flexion of neck (same side)

  • Bilateral contraction –anterior neck flexion (nod)

Hyoid Muscles

• Supra vs Infra hyoid

Suprahyoid

• Action: Elevate Hyoid bone (important for swallowing)

Infrahyoid

• Action: Depress Hyoid bone (important for swallowing, speech)

Digastric

Stylohyoid

Geniohyoid

• Geniohyoid is deep to Mylohyoid

• O: Mandible

• I: Hyoid bone

Mylohyoid

• O: Mandible

• I: Hyoid bone

Suprahyoid Muscles: Blood Supply

• Suprahyoid muscles supplied by branches of the facial and lingual arteries

Omohyoid

Located most laterally of all infrahyoid muscles

Sternohyoid

O: sternum

I: hyoid

Sternothyroid

O: sternum

I: thyroid cart

Thyrohyoid

Infrahyoid Muscles: Blood Supply

• Infrahyoid muscles supplied by branches of the superior thyroid artery

Posterior Neck Muscles

• Responsible for supporting and stabilizing the head and neck

• Superficial to Deep: Trapezius → Splenius capitis → Levator scapulae → Semispinalis capitis

Trapezius

• Superficial muscle of the back. Paired, trapezoid-shaped muscle

• O: Base of skull (occipital bone), spinous processes of C7-T12

• I: Scapula (acromion + spine), lateral aspect of clavicle

• Action: Upper fibres extend and rotate the neck

• Innervation: CNXI

Posterior Muscles: Splenius Capitis

• O: Cervical vertebrae

• I: Mastoid process (temporal bone), occipital bone

• A: Neck extension

Posterior Muscles: Levator Scapulae

• O: Cervical vertebrae

• I: Medial border of scapula (above spine)

• A: Movement of the scapula

Posterior Muscles: Semispinalis Capitis

• O: Cervical vertebrae

• I: Occipital bone

• A: Neck extension

Venous Heart

Arterial Heart

Arch of the Aorta

Upper limb arterial supply

• Supplies blood to upper limb and branches off

• Travels under the clavicle

Head and Neck Arterial Supply: Vertebral arteries

• Vertebral arteries: branches of the subclavian arteries

• Supply: spinal cord, brainstem, brain

Head and Neck Arterial Supply: Carotid Arteries

ICA: Travels to brain via carotid canal

External Carotid Artery Branches

• Superficial temporal artery: Supplies temple, scalp

• Facial artery: Spiral like appearance. Supplies face (e.g., lips, external nose), neck (e.g., palatine tonsils)

• Lingual artery: Supplies tongue, mouth
  

Posterior Thorax Arterial Supply

Anterior Thorax Arterial Supply

Subclavian —> Internal thoracic a. —> Anterior intercostal arteries

Thoracic Aorta Branches

Head & Neck: Jugular Veins

Head & Neck: Subclavian & Brachiocephalic Veins

Jugular Veins —> Subclavian Veins —> Brachiocephalic Veins —> Superior Vena Cava

Head & Neck: Facial vein

• Drains into internal jugular vein

Thorax Venous Drainage

Azygous Vein —> SVC

Abdominal Aorta

Abdominal Aorta Unpaired Branches

Celiac trunk

• Stomach, pancreas, spleen, liver & gall bladder, small intestine (proximal duodenum)

SMA

• Pancreas, small intestine (distal duodenum, ileum, jejunum), most of the large intestine

IMA

• Distal large intestine to rectum

Pelvis Arterial Supply

Pelvis Veinous Drainage

Abdominal Veinous Drainage

IVC & Abdominal Aorta

The Lymphatic System

Part of the immune system, composed of lymphatic vessels, lymph nodes & lymphatic organs (e.g., spleen, tonsils)

Lymph Nodes

• Organs of the lymphatic system linked through lymphatic vessels

• Sites of immune cells; act to filter foreign particles

The abdominal wall

• Muscles that enclose the abdominal cavity

• Protects abdominal viscera and stabilizes/promotes movement of the trunk

• Assists in abdominal compression for forceful respiration and defecation

Pelvic bone anatomy

Thoracic cage anatomy

Divisions of the abdomen

• Quadrants (4) and Regions (9)

Anterior/lateral abdominal wall muscles

1. External oblique

2. Internal oblique

3. Transversus abdominus

4. Rectus abdominis

Important actions

• Trunk flexion, Lateral trunk flexion, Trunk rotation

External oblique

Internal oblique

Thoracolumbar fascia

Transversus abdominis

Rectus abdominis

Tendinous intersections

• Fibrous bands separating the rectus abdominis muscle

• Allow for segmented contraction of rectus abdominis

Rectus sheath

• An aponeuroses of the external oblique, internal oblique, and transversus abdominis

• Encloses the rectus abdominis

• Converges at the midline at the linea alba

Linea alba

The arcuate line

• Located just below the umbilicus and above the pubis

• Marks a change in the composition of the rectus sheath

Above the arcuate line

Below the arcuate line

Inguinal region

Inguinal ligament

Inguinal canal

• Passageway through the lower abdominal wall

• Runs from the deep inguinal ring to the superficial inguinal ring

Borders of the inguinal canal

Inguinal canal Anterior wall

Inguinal canal Posterior wall

Inguinal canal Roof

Inguinal canal Floor

Contents: female inguinal canal

Contents: male inguinal canal

Posterior abdominal wall muscles

1. Psoas major

2. Quadratus lumborum

Psoas major

Quadratus lumborum

Abdominal Wall Innervation comes from...

1. Intercostal nerves

2. The lumbar plexus

3. Dermatomes

Intercostal nerves

• The ventral rami of thoracic nerve roots T2 –T12 form the intercostal nerves

• Travel between the ribs

• Inferior intercostal nerves (T7 – T12) supply motor innervation to the abdominal wall

Lumbar plexus

Dermatomes

Abdominal Wall Blood is supplied by...

Internal thoracic artery

Superior epigastric arteries

Musculophrenic arteries

Inferior epigastric arteries

Abdominal Wall Lymphatic drainage

• Lymph from the abdominal wall is filtered in the lumbar and inguinal nodes

• Is then drained into the cisterna chyli then into the thoracic duct

Oral Cavity

Digestion:

• Ingestion: receives food

• Mechanical digestion: breakdown of food (mastication)

• Chemical digestion: via salivary secretions

• Swallowing: move food to esophagus

Divisions of Oral Cavity

Oral Vestibule

• External border: lips and cheeks

• Internal border: teeth and gingiva

Labial frenulum:

• Tissue that connects the lips and gingiva (gums)

Oral Cavity Proper - borders

• Roof: hard & soft palate

• Floor: tongue & floor of mouth

• Posterior border: oropharyngeal isthmus

• Anterior border: teeth

Oral Cavity Proper - Arches

Palatine Tonsils

• Lymphatic tissue located between palatoglossal & palatopharyngeal arches

• Immune function

Oral Cavity Proper - Lingual frenulum

The Tongue

• Bundle of skeletal muscle

Functions:

• Positions food between teeth

• Mix food with saliva

• Forms bolus

• Initiates swallowing

Lingual papillae (taste buds)

• Taste receptor cells

Sensation Innervation:

• Posterior 1/3: CN IX

• Anterior 2/3: CN VII