Neck and Pelvic Anatomy Essentials

Neck Anatomy

The head and neck join the upper chest. The neck comprises skin, fibrous muscles, major vascular elements, lymph nodes, organs (cervical larynx, cervical trachea), and glands (thyroid and parathyroid).

The skeletal neck includes the cervical spine.

• Platysma (2): Thin ring from the superclavicular zone to the face, deep chin.
• Sternocleidomastoid (2): Lateral neck, from the thorax to the temporal and occipital mastoid bones.
  • Origin: Lower insertion and command of the sternum and below the clavicle.
  • Lateral/External: External jugular vein, ending with the subclavian, used for serum.
  • Medial/Internal: Vasculo-nervous bundle, primitive carotid artery, internal jugular vein, neurogastric nerve.
  • Double Innervation: Branches of the nerve cord and cervical plexus.
  • Action: Raise the clavicle, secondary accessory inspiratory muscles.
• Scalene Muscles (6): Deeper, from the cervical spine to the first and second ribs.
  • Action: Raise the first and second ribs, accessory or secondary inspiratory muscles.

The anterior neck is formed between the anterior and posterior triangles. It includes the mandible, hyoid bone (suprahyoid and infrahyoid areas), sternum, and anterior border of the sternocleidomastoid, in relation to the thyroid and cricoid cartilage.

Respiratory Organs: Larynx and cervical trachea, followed by the cervical esophagus and pharynx. The thyroid gland (27g) is located near the first two tracheal rings. Each lobe forms a triangular prism. At the back of each lobe are the parathyroid glands (2 pairs of lobes, 1g total).

Pelvic Anatomy

Ovaries

Located in the pelvic excavation, 4-5 cm, 6-8g, in the ovarian fossa, 15-20 cm in front of the sacroiliac joint.

• Above: External iliac vessels.
• Below: Internal iliac vessels and ureter.
• Utero-ovarian Ligament: Tubes to the ovary.
• Mesoovarium: From the uterus.
• Lumboovarian Fossa: Internal iliac, top of the ovary (peritoneal, fibrous, muscle, blood vessels).
• Irrigation: Utero-ovarian vessels.

Fallopian Tubes

10-12 cm, capture the egg. Three parts: lateral (pabello), body (medial), intrauterine (internal). Abdominal orifice cervix. Peritoneum, smooth muscle, mucous tissue. Supplied by the utero-ovarian artery, and uterine artery towards the inside.

Uterus

Located in the pelvic excavation on the pelvic diaphragm and perineum, behind the bladder, in front of the rectum. 8-10 cm, muscle. Three parts: body (extensive), fundus (highest), isthmus (narrow portion), and cervix (below), where the vagina attaches.

• Vaginal Fixation: Supravaginal and intravaginal portions.
• Layers: Peritoneum, thick muscle (myometrium), mucosal lining (endometrium).
• Cervical Canal: Communicates with the vagina.
• Anteflexion: Open to the front between the uterine body and cervix.
• Anteversion: Uterine body axis in relation to the pelvic axis.
• Irrigation: Uterine artery, forming flexuous arterial branches.
• Douglas Pouch: Between the uterus and rectum.

Vagina

From the cervix to the external genitalia, 8-10 cm.

• Top Opening: Relation to the cervix.
• Bottom Opening: Relation to the vulva.
• Function: Menstrual period passage, childbirth, penis receptacle.

External Genitalia (Vulva): Mons pubis, labia majora, interlabial space.

• Mons Pubis: Convex on the pubis, skin, fat, and hair.
• Labia Majora: Below the mons pubis, 10-12 cm, two-sided, lateral with hairs, internal with lip opposite.
• Clitoris: Interlabial space, sponge body, 0.5 cm.
• Labia Minora: Contains the urethral opening and lower vaginal opening, covered by the hymen.