Minor Head Trauma: This is the most likely diagnosis given the scenario. A fall from a bed can result in a minor head injury, such as a bruise or a small laceration, especially in a 7-month-old child who has limited mobility and is still developing protective reflexes. The child's age and the nature of the fall suggest that the impact might not be severe enough to cause significant internal injury.

Scalp Hematoma: A fall onto a hard surface can cause a scalp hematoma, which is a collection of blood between the skull and the scalp. This condition can be painful and may cause swelling but is usually not life-threatening.
Linear Skull Fracture: Although less common, a linear skull fracture could occur, especially if the child landed directly on their head. This type of fracture is often seen in falls from a height onto a hard surface.
Concussion: A mild traumatic brain injury, or concussion, is possible, especially if the child's head struck the floor or another hard object with significant force. Symptoms might include fussiness, vomiting, or a brief loss of consciousness.

Intracranial Hemorrhage (ICH): This includes subdural, epidural, or subarachnoid hemorrhages. Although less likely, ICH is a critical diagnosis that must not be missed due to its potential for severe morbidity and mortality. Symptoms can be subtle at first, including lethargy, vomiting, or irritability, and may progress to more severe neurological deficits.
Abusive Head Trauma (Shaken Baby Syndrome): It's crucial to consider non-accidental trauma, especially in young children who cannot communicate the events leading to their injury. Suspicion should be raised if the history provided does not match the severity of the injury, if there are other signs of abuse, or if the child has unexplained injuries.

Depressed Skull Fracture: This is less common and usually occurs when there is a direct blow to a small area of the skull, causing it to depress inward. It's rare in falls from a bed due to the nature of the impact but could occur if the child's head struck a corner or edge.
Basilar Skull Fracture: Although rare, a basilar skull fracture could occur from a significant impact to the head. This type of fracture involves the base of the skull and can be associated with specific symptoms like cerebrospinal fluid leakage from the ears or nose, or bruising behind the ears (Battle's sign) and around the eyes (raccoon eyes).